The SX Jazz basses and the Fenders both weigh about 9 lbs, so I don't see why the weight of the SX is a factor when comparing to the Fender.
There is nothing on Fender's site about MIMs being shielded. If you go to
this thread you will see info on how to shield your jazz and people posting as they did it over time, some in the last few months even saying how much it helped their Fenders to do this.
My Scorpion's tuners seem fine. They don't grind and they hold a tuning well.
The fret ends are nicely finished. I did the silk scarf slide test and it passed.
The neck was sticky and it took me darn near 3 minutes to satinize and it loaded up a piece of 0000 steel wool so full of powdered finish that I had to throw it away and it probably cost me a quarter! Hopefully they will get that straightened out before it costs them too many sales.
My bridge pickup had lousy output until I adjusted it closer to the strings. The bass needed a pretty thorough setup; truss rod, string height and intonation all needed adjustment and this took me the better part of an hour to get right, though a substantial portion of that was playing to try out action adjustments.
The electronics don't seem too bad to me. I wired a series toggle in. I did wick away more solder than I put back; they were a little heavy handed with that. But there were no shorts and everything was wired correctly. The pots are small form factor but are standard issue as far as the specs and they work well without any noise.
My bridge pickup is misaligned about a millimeter. I took the pickguard off just to look and had no stripped screws and was surprised to find it fully finished and the routing for the neck pickup so precise that the pickguard could have been optional.
The gig bag is not padded, but it was included in the price ($119 + $13 S/H) as was a decent strap (a little thin, but with a shoulder pad that has a matching Scorpion on it as does the gig bag).
The MOP inlays look very good even close up. I think it is real, but I can't be absolutely certain.
I like this bass more every day. Plays like a dream with the satinized neck and sounds great. I have put it in the hands of guys who have gigged for years and have received nothing but compliments.
It is possible that you would like a MIM this much. It's possible that I got lucky and they aren't all this good. But the good reports seem to outweigh the bad (if you can call the ones that say they are good for the money but don't compare to Fenders bad).
...SXs are Heavy, Poor output on the bridge pup, horrible tuners the worse i have ever seen metal scraping metal binding and snaping sounds. The necks are like they were dippped in glue to glossy and very sticky a lot of sanding needed to get em playable in humid hot weather outdoors or when your hands sweat.Every screw was stripped out on the pickguard and two on the jazzes control cavity had to add toothpicks when i removed them to sheild it. BUT for 125.00 shipped it did sound and play great and was gigable..with work and more $$ they could be up to a MIM...a MIA or highway 1 thats a laugh..even a MIM has sheilding now all have CTS pots and good wiring...Sx have tiny junk pots and junk wiring...plus there is no resale i sold both mine one for 75.00 the other 90.00..MIM i get back most of my money and i need little mods a great neck , good tuners, wiring,and my stock pups are fine.I did at one time jump on the TB SX wagon but fell off when i bought 2 and tryed them for a while...i guess you need to try it too.