After trying Labella 760FS (45-65-85-105), 760FL (43-60-82-104), and Fender 760ML (50-65-85-100)'s I was none too satisfied.
First, The Labella FS set is very nice. Dark, thumpy, and with some nice tension. I don't think if you're starting out on flats you can go wrong with this set. People talk about flats having higher tension, but I don't see making the switch with this set to be a problem. For most it will be a quick adjustment. Unfortunately, at the time I got my new bass, JustStrings (they're in NH, I'm in MA, so I always use them) was all out, so I went with the Labella FL set. It's not bad, but I honestly felt like the set was out of balance a bit. The D (.60) seemed light and zingy sounding compared to the E & A and the G (.43) while fine with those two, was dead and lifeless against the D. I looked around and read up that it just takes time for them to break in. The FS's always sounded great out of the pack, so I wasn't convinced. To give credit to this set though, they are just as thumpy sounding as the FS's, only a little lighter with of course less tension. I have no doubt that once broken in they'll sound great, but I'm impatient. I don't play enough to break in strings quickly and I don't want to wait a year for them to sound good at my rate.
Up next was the Fender 760FL set because 1) My store had them in stock 2) They were medium gauge with the exception of a .100 E and a .50 G. The heavier G was nice, and of course I had no problem with the standard gauge A & D. But, in the end, the E was too light at .100. Compared to the first two Labella sets, the Fenders are just a tad punchier and darker. By comparison, the Labellas do have a tiny bit of zing, but IMO, nothing to concern yourself with. Tension is good as well. I'd say this set is equal in tension to the Labella 760FS set.
I'm a huge Jamerson and Bruce Thomas fan, so I want a big, deep sound, with a decent amount of mid range. Not being happy with the last two sets of flats and already knowing what the Labella FS set was like, I wanted to try something different. It wasn't a surprise to me that I loved both James and Bruce's tones so much and they both used heavy guage strings (although Bruce used Rounds). So I decided to get the Labella Jamerson 0760M set. I was a bit nervous after reading reviews on here because of such phrases as "High Tension", "Bridge Cables", "Steel Bars", and "Major Neck Adjustment". But I bit the bullet anyway.
So I ordered a set of JustStrings and got them the very next day after shipping. They beat their old average by one day, very nice

At this point I just have them on, stretched by hand a bit, setup, and intonated but I haven't physically played them all that much yet.
My initial impressions are WOW!..just what I've been looking for. These strings are huge sounding, but not overwhelming so. They are definitely deeper than the Labella FS set, but what stands out the most is how even they sound. They are the most balanced set of strings I've ever played. Not just in tone, but in volume all over the neck as well. I'm not afraid to play notes lower down on the G for fear that they'll sound thinner or weaker in comparison. These strings are brighter out of the pack than the FS set, which I have read. There is still a moderate absense of finger and fret noise as with flats, but the fret transition on slides and the fret "clank" when pressing down is just a bit brighter than you'd expect on some frets out of the pack. But, it is honestly a minor, minor thing. They sound great now and I know they will break in beautifully. These things even slap pretty nicely as far as the tone is concerned.
As for feel, these ARE big strings (.52, .73, .95, .110) so they will take some getting used to. For me it will only be a slight adjustment, I don't know why, but it's not that big of a deal. In fact I love the big feel under my fingers. To me they make my Precision FEEL like a Precision, if that makes any sense. Tension wise, they are a bit higher tension than the FS, but in a strange way they have a softer feel. I definitely do agree with some remarks that they feel like steel bars, or that you'll get Tendonitis from playing them (take this from a guy with Carpal Tunnel already). In some ways I think the solid feel will help because the thickness of the strings allow them to speak more easily. Less force is required to get them to resonate (again, the opposite of what some has said, but that's why it's personal perception), so they actually are easier on your right hand. Your left hand might have to work a bit more, but once you get used to them I think it's a minor adjustment. Oh and if it helps anyone, I have relatively small hands, so you don't need bear claws to play these things.
As far as adjustments to the bass goes, all I had to do was give the truss rod just a tad more than 1/8 of a turn. I do have the action SLIGHTLY higher than I would with a lighter set, but I think that works both in tone and feel for this set. I did however have to move the E saddle back quite far in order to intonate it. The other 3 strings intonated pretty easily, or were already pretty close to spot on.
I only had a few problems/concerns with these strings:
1) At least on my Highway One P, the tuner hole was a very tight fit for the E string, so it took some work to get it to lock into the tuner before I could start winding. I accidentally cut the string too LONG, which after having to unravel the string and try to give it another shot, didn't help
2) There is some talk about having to get your nut slots widened, but my nut is fine...though the D saddle is just a tad too narrow, enough so I have to press the string into the slot. This just gives a fraction of a second delay when tuning because there is more friction on the string at the nut. I'm going to have to put some sandpaper on a tooth pick or something and widen it a tad. That would work right? Anyone? Bueller?
3) I was nervous as hell tuning these up. You can definitely feel the tension in the tuners when you tune up and with every creak and groan from the string I was afraid the string might snap if I went higher than I should, so be VERY careful when tuning these up. Honestly if you're tuning EADG, these are the heaviest gauge strings I think you should use. Any heavier and you probably will snap a string. No worries though, they're of course fine for standard tuning, just pay attention to what you're doing.
4) Finally, tuning is a bit more tricky, atleast with my tuners. I find that I have to be much more incremental with the tuners than with lighter strings. I kept going from flat to sharp in an instant while trying to hit the pitch. But I suspect a lot has to do with the strings being new. Once they're broken in it probably won't be a problem.
That's it. Thanks for taking the time to read this. With all the threads on this and other Deep Talkin' sets I hope it helps. I'll probably try and get audio up eventually. These strings will definitely get you to Jamerson land and back. I'm actually going out tomorrow to get either a pencil eraser or some weather stripping just for that purpose
