Well, it depends on what is your target market. If its for higher-end users, those who digs for space, 100 watt stacks, 100 watt bass amp, a nice drumset, a decent powered PA, good mics, etc. Check out places like Guitar77's, Wakemeupmusic. price ranges from $15-18/hr
if you're looking at cheaper rental, decent equipment, like mikemann's studio is more than enough. His rental rates are very reasonable, with a big room, decent amps, decent drumset, and everything. free iced water also!
location wise, you can say its important. Not only for you, but also for the users. Some of us carry our own gear, thus, if its a place that's difficult to go, it'd be very difficult for us to reach, and we'll most probably go for those easily accessible places. Eg. town area, but rental prices will vary from here too.
Last but not least, friendly people with smiles count a lot. Eg. Rui my man, haha..from G77, and the peepz at WMUM have one of the best ratings for the studios i've visited so far. Yupz...
p.s. i'm a consumer. not an advertiser. based on my experiences only. =)