I wouldn't consider 10mins chess to be real blitz... FIDE defines it as "accelerated chess".
My favorite is 3+2 because the increment ensures that a real chess is attempted to be played, instead of monkey chess which happens without the increment.
3 2 does not attempt to be real chess. A 40 move game doesn't even last 5 minutes
10 0 lasts more than twice as long, giving a much greater chance to let thought into the game.
3 minute no increment is my favorite followed by 5 minute no increment.
I have no qualms flagging my opponents and I have no problems when they do it to me. With no increment the clock is essentially another imbalance in the position and I think the extra dimension it adds is fun.
10 minutes
Personally, 3|2 is my favourite since it is not too long and means that it is difficult to force someone to lose on time. Therefore, it seems the most logical and friendly and is often played with less salt etc. (at least from me). 1 min, 2|1 and 3 min are shorter than I like. It is highly likely to run out of time from my experience at these time controls and in 2|1, the increment is not long enough. 10 min, 30 min and 15|10 are too long (especially 30 min) and do not provide the flexibility of taking a break to do something else such as read the forums or read the news that shorter time controls provide. Although I recognise that in these longer time controls do allow for more thinking time and undoubtedly better quality games, they are simply too long. 5 min and 5|5 are also quite good for me with a good balance of time and flexibility for concentrating deeply on other things, not fixed or distracted by a single game for up to an hour or more.
Overall my rankings are as follows:
3|2
5 mins
5|5
3 mins
10 mins
2|1
1 min
15|10
30 mins
I hope this has been helpful to all those reading this. Do be free to persuade me otherwise. I am always open to different opinions as long as they are well explained.
Please, explain why: frequent use in tournaments, no time trouble, more dynamic or something else?
Erik wrote about that. https://www.chess.com/article/view/interesting-chess-data-time-controls-and-game-results
10 0 was the most popular.