When I first started playing online, I preferred normal speed, because I wasn't very good and I felt like I was getting my money's worth that way. It was more about how much I was spending per hour, rather than how much was I making, per hour.
I think that, when you turn the corner into profitability, we're looking increasing our throughput of
hands. ie. if you are playing a winning strategy, you want to get as many hands in as quickly as possible. As such, Turbo's and hypers become more cost effective, especially if you start deep stacked.
Trouble is, you get short stacked pretty quickly and you're going to reach a point where you are shoving hands to prevent getting blinded out, rather than shoving hands that are good shoves.
But at the end of the day, there is a variety of games which suits a variety of styles and reveals its excitement in a variety of ways.
When I play live with my friends, I prefer slower games because it is about having fun with my friends. But otherwise, I prefer games which are going to be wrapped up in 4 hours or less...preferably MUCH LESS.
Cheers,
JT