I use a set of Lekato WS-70 - UHF, so neither 2.4GHz or 5.8GHz. I've had great results with these - gone on walkabouts round the entire pub before. Lasts a 3 hour gig on a full charge no problem (I think the full life is 7 hours per charge, but I wouldn't like to risk playing 2 gigs back to back without charging in between). Seems to handle active basses OK (I've used them with my Sire Z7 in active mode without issue).
Also can be had for anything between £30 and £60 depending on where you look. I bought these for a first stab at going wireless and honestly I don't think I need to "upgrade" as these have been doing the business for me for the last 6 months or so. If anything went wrong with them, at these prices I'd probably just buy another pair.