I agree, I just put these into my '90 MIJ Fender Jazz. Amazing pickups, especially with flatwounds, I have not played a vintage 60's jazz, but I do know a good tone when I hear it. These pickups are nice and fat, get a strong growl when played on the bridge. I boosted my low mids on my Markbass just to really get a full punch from it. The high mids stay present on most settings and they are the jazz bass sound to me. The articulation that I get from each pickup is unparalleled, and they are incredibly versatile depending on how you set up your amp.
I play in an "Indie" band, useless as that may be. The best comparison would be similar to Radiohead, As Tall As Lions, Sigur Ros, and Ataxia to name a few. The pickups sit in great on a three piece and are very clear when using effects. The bridge pickup can really snarl especially with an overdrive pedal, while the neck pickup has a fat punch with some grind. I wouldn't call them modern sounding personally, nor would I say they are impossible to tame, you just have to set up your amp for your sound and playing style. They will bring out good and bad parts of your playing.
My Aguilars are fat, warm, a little grind or a lot depending on your style or settings, and quite frankly clear. I got very tired of muddiness, I don't hear it with the Aguilars, and the 60 cycle hum is present, but not overly so.
The not so good about these pickups, there is not a lot of natural punch, it's not hard to adjust, but a slight bump in the low mids helps them, at least through my rig (Markbass LMT800 -> SWR 4x12). The 60 cycle hum is present, so if you cannot tolerate it I would maybe look elsewhere, but if you don't mind a little bit then it's not an issue. I think they shine with flatwounds, I didn't tinker too much with rounds on these pickups.
I don't slap usually, but when I had rounds on my jazz they sounded good to me, though slightly hollow on a slap sound, but I don't play slap as I said and don't dial my tone in for it either. So try it out for yourself, but at $150 a pair, I think the Aguilar's are a winner for me. I'm going to try to get a pair for my fretless.
-Jake