Quote Originally Posted by Biggus View Post
The fact that GSA is so widely considered a bad class suggests that very few people want to play a mage (or any other class for that matter) with 8 Con. I'm sure some people do, and some of them even make it to high levels, but you're talking about a pretty unusual situation here.
I agree that very, very few players are going to give their wizard 8 con, but an elf wizard with a lowish point buy likely only has a 12, so at level 15 with a con belt they'd be losing 25 or 40 hp counting the 20 they gain back.

And if faerie mysteries initiate is allowed, they're just gaining 20 and they can buy a str or dex item instead. If not, just don't take the 10th level, or maybe the 9th, and you've gained a bunch of resistances, some immunities, DR, natural armour, and 50-75% fortification.

You'd still be better off with 2-3 more spell levels, but there's much worse prestige classes out there. I probably wouldn't take it for a straight wizard, but I might consider it for a gish build.