If you aren't worried about getting laid, totally go for the portaledge! They are awful comfy - then again I've only slept on one after a hard days aid climbing. I'm pretty sure laying down on a rock lodge would have been equally as appealing at the time.
Get a used portaledge for a steal because someone realized they are never going to climb a wall, and then used the remaining money to get a lightly used mattress. Pretty effective to get a mattress off students or people in general who are moving and can't take their $1000 mattress with them. Of course, make sure you try it out first because you spend about 1/3 of your life sleeping, so you'd better like it. All in all, I think you can come out below $700/800 total depending on what your local used mattress market looks like. Well-price double ledges show up on MP regularly, it just depends how picky you are.
But if you have to choose, get the portaledge, because if you aren't training even when you're sleeping, then you're not maximizing your potential ;) There's a good passage in Kiss or Kill about sleeping on plywood or the like to get used to bivies.