I personally really like Age of Pinballs by Ask Homework. The physics are really nice, and fun to play. There is a lot of tables (there are 14 tables right now, and a new table is comming out once every month), but some of them are pretty similar, but still great value. Zen Pinball by Zen Studios is another awesome game, with nice physics, and table designs (with fantasy elements). But it has a lot framerate drops, but still worth playing. You get one table for free, but you can buy five additional tables in app) The Pinball Arcade by Farsight Studios is the newest pinball game, but also the most realistic. The tables are accurate recreations of real tables from the past. With this game you have to buy the 4 tables separately. These pinball tree games are my absolute favorites, but Little Wings classic Pinball Tristan is also pretty good with its advanced physics...
I wouldn't say that Zen Pinball has "a lot" of framerate drops on A5 devices. I guess you can argue that any framerate drops is unacceptable, but I have yet to have it affect gameplay really. Pinball Arcade is a beautiful simulation. But I'm findings Zen to be a heck of a lot more fun.
It would seem that pinball arcade will be the one with the most content eventually, they've promised new pinball tables monthly and with like 90% of the top 40 pinball tables of all time promised to come, that's a hell of a lot of pinball! For now you can get their 4 launch tables for $9.99 Zen will probably be running a close second to that....on Xbox I think they have like more than 20 tables and they are gonna port most of them if not all. I would be hard pressed to choose between the two - just get both and you'll have more pinball than my grandmother!
Pinball Arcade and Zen Pinball for me. Very polished games I've got some more 'basic' pinball games also on my ipad, Age of Pinballs as theres quite a few more tables, like i say more 'basic' than the others but does make a nice change at times