You are definitely aware that it's a slower option when playing turn based, but I haven't found it to be particularly annoying. The game is probably "easier" on turnbased, in as much as the player can bring their skill to bear against the AI a lot more easily. It makes it easier to focus fire, and you can get away with more of a glass cannon party design to compensate.

OTOH, it does seriously adjust skills and abilities with durations. The granularity of skills/spells is in rounds, which I guess is ~4-6 seconds, rather than in tenths of a second. It takes of a lot INT/levels to increase durations, and those increases are quite powerful. Party power progression is more of a step function as opposed to linear, so there are some parts earlier on that may actually be a little harder if you rely upon CC and/or summons.