Never been to Hersonissos, so can't comment on it, but Stalis is fairly lively without being over the top.
It's difficult to say whether or not it's "too quiet" because that's obviously a personal opinion and I don't know what you're used to.
Stalis certainly isn't as lively as resorts like Faliraki, Mallia, Laganas etc, but it does have lot's of bars and a few clubs.
It's also got a great beach and (in my opinion) a number of very good restaurants, assuming you want Greek tavernas rather than burger joints etc.
I'd recomend it for someone wanting a lively holiday but stopping short of the 18-30 type resorts.

thanks rigler,
it does sound nice. what are the beaches like in stalis. are they quite narrow, will be like sardines during july/aug or will you always have a place to put your towel. Whats the water like & sea temp like at that time of year. is it crystal clear & white sand.
thanks a million.

Melissa,

I'd definately back what Rigler64 says. Good post and summed up Stalis well. I went to Stalis at the start of September with my girlfriend and it was just what we wanted. There were plenty of bars - some lively, some quiet - and plenty of good quality restaurants. I would definately recommend the resort over Hersonissos.

The beach in Stalis is much better for a start (soft sand, quite long and although not that wide we always got a sunbed and never felt over crowded) and as it is located between both Hersonissos and Malia you have more choice if you fancy a change of scenery at night.

Don't think you'd be disappointed if you chose Stalis. We certainly weren't.

Steve