I've run a few FL campaigns and I love the system and its setting. I'd also suggest checking out Dragonbane as that's a nice sweet spot between FL levels of punishment (Mages get a pretty raw deal in FL IMO) and D&D.

Dragonbane uses a simple d20 roll under system, character advancement is very organic - a result of its BRP roots, and characters recover Willpower by resting rather than having to find ways to push rolls and risk getting broken all the time. This makes spellcasters a lot more viable than in FL.