505 doesn't have searching, but has bookmarks (and so does the kindle). I think though, if you get the 505 and use Calibre you should be happy with the 505. I think if you use it for two months you might have a hard time giving it up
If you get it, make sure you grab a PSP charger before you go, if you don't have computer access. It's cheaper than the AC adapter for the Reader and works perfectly. I'd recommend a booklight, but it sounds like you have one already.