Um, it's actually more expensive at the micros at 6.67%. $10 and $25 have always been 5%.
The rake at $10NL at Full Tilt has never been 5% as far as I'm aware of. Up until recently, the rake at 10NL was 10%, capped at $2 per pot. Like iopq says, he was running at 1BB/100. After 15,000 hands I was running at like -0.5BB/100, which, when I adjusted for a 5% rake worked out at about +2.5BB/100.

They've made it now so that everything at 10NL and below is 6.7%. If you're getting 27% rakeback, the rake becomes effectively 5% like you'd find elsewhere (how convenient).

As for whether or not you want to play there...