The games are highly ddifferent and it depends on what you want.
JUMP is a more party-oriented game with strong play on position, items and such (like Smash Bros). Really, the smash bros description is appropriate, it plays very much alike regarding the whole stage design and jumping around and stuff. It has a traditional health system so no smashing out necessary (though making an enemy drop off the stage does net you a kill) and generally less air time but the many character options make it varied with a collection aspect. I don't know how well it's balanced and the moves of each character are limited (moreso than Smash Bros, I think). Missions in Singleplayer have some variety, not all are about getting the most kills, some involve e.g. getting more items than your opponent or not taking ANY hits until the timer runs down.
Bleach is a more traditional fighter like Street Fighter. It's said to play out like Guilty Gear and while it has some of the complexity in terms of all the different special modes you can trigger I can't say they feel much alike when playing. The special cards you get can really wreck the game if the right ones are played (sup, two 300% supers in a row?) but I think you can limit it if you hand people less nasty decks (or disable them completely). Outside of those I think it feels closer to Melty Blood or Eternal Fighter Zero (which may still be close to Guilty Gear). Special attack inputs are simple and easy to remember while accepting any button at the end (no need to remember which button is needed though the button does change the effect in a predictable way), you get the flashstep (or dash for characters who don't have that fluff-wise) which cancels out of an attack or block and teleports you, allowing for prolonging combos or quick dodges. The combat is about as deep as any other 1v1 fighting game with different attack heights, special attacks that can be varied and of course combos (both ground and air). It even has a training mode that teaches you some combos for your character to get you used to e.g. airborne comboing or cancel by flashstep. It also makes use of the Bankai supers in more creative ways by e.g. letting you control the slashes of the giant mecha you summon for maximizing its damage. Characters play a lot more varied than in Jump, some have really prominent unique traits like e.g. a second character you can order around or a super that instakills if it hits the same opponent twice (and of course the controllable bankais).
Personally I prefer Bleach, it's more fun to play, Jump isn't as good in play and relies more on brand recognition for its fame IMO. Real combos don't seem very doable in Jump.
Mind you, I've only played the first game of each series but I don't think the fundamental gameplay has changed much.