I personally like tournaments over $100 and at least 30 minute blind levels. I feel has if I can get a lot of play in. My simple win/cash rate is ~28% of large buy-in. I credit amount over $100 a large buy-in. And around 30k in chips. My ROI is about 150%. I don't play as much as like so I'm sure this number would change.
Any buy-in under $100 is less preferred. Starting stacks vary but levels on average are 20 minutes. Mostly these tournaments are the ones with more quickly advancing blind levels. I am not a big fan of these but do play them do to their availability in my local brick and mortar. Again my simple cash rate is about ~25% or slight less. My ROI unfortunately is 95% currently do to a losing streak in these games and not playing often. I have recently changed my style somewhat and therefore my results my take a while to stabilize.
At the moment I am trying to build my bankroll , I play mostly 1/180 on Stars and some of the Bigs like 0.55 , 1.10 or 2.20. Sometimes i give a shot at hypers 6max 0.27 and 0.55.. they have great value if you know basic push /fold stradegy.. People punting a lot there!! But IMO nothing compares to a MTT deep run.
Ya, I love winning something for nothing. freerolls can be very fun. It feels nice to win a 1000+ player tournament even though a bunch of them were donks. I'm waiting for some pokerstars to come back to the US with 10,000 players on before I start making some serious deposits.