I can't speak for everyone, but I personally don't like or prefer UMD. I just like the selection of titles for UMD compared to what they're selling on PSN. What I hate is how limited the selection of PSP games on PSN is. There is a serious lack of RPGs on the PSN store, and this may just be my opinion but the line up of RPGs on the PSP is what makes the system great. Yet there are games even from big publishers severely lacking on PSN for the PSP. I heard Kingdom Hearts wasn't on PSN because of Square-Enix's contract with Disney or something...ok, fine...They have an excuse, but why the hell haven't Square-Enix put Crisis Core on there then? It's not like any contracts are limiting them from doing that.
I don't know who's fault it is, Sony or the third party publishers, but if they want people to buy their games, they should be making them available as many ways as possible. The number of games should be increasing, but it seems like no publishers are making any effort to redistribute older PSP games on PSN, and with the launch of the Vita, new life could easily be breathed into some older titles. We shouldn't be removing titles like XSEED did. I know at least one game I would have bought has actually been removed from PSN. Brave Story was on there at one time, and it no longer is a title available when I searched.
The other problem I have is how inconsistent pricing of digital distribution can be for consoles. I really hate the half-assed approach Sony (and microsoft) do with their DD services. It's not like Steam where the prices usually stay up to date with the latest MSRP. One title I'd like to get on PSN for my PSP is Hot Shots Tennis, but it's hard to justify the $20 price they're charging, when I go to my work, and I see a PSP bundle they have which includes Hot Shots Golf: Open Tee, and Hot Shots Tennis bundled together for $14.99! Not a sale price, not a clearance price, but the usual retail price. It's nonsense, it's like they put the games up for sale on the service, and then just forget that it exists and let the price stay the same forever. There have been a few exceptions, but not enough. Prices don't frequently go on sale like Steam either.
Sorry, didn't mean to go off on a rant. Maybe the PSP Go wouldn't have been such a flop if they were on top of this shit. I want to support Sony, and make the give them all my money with the Vita, but they need to get their head out of their ass.