I'm not really sure, you'll have to wait for more responses but you could always start the game without the mod, try the first area like Tutorial or the beginning and then switch it on and try and see the difference. The main difference is the mobility of Geralt, it feels easier moving around but not necessarily are you much faster.

Hmm, now that you mention it I've some vague memory about it blocking at least two times but oh well. We'll have to see how the new Quen works against tougher enemies.

I noticed Axii doesn't work at all or it was was made intentionally to only stun an enemy instead of changing their allegiance. It's somewhat useful against one bigger enemy if you've allies around you but otherwise it's a waste of vigor.

Both Igni and Aard have AOE even on level 1, somewhat imbalanced but that may change later.

No, this is NOT recommended for a first playthrough.

Also, unless you just want to bug-test you may want to hold off downloading this until Flash fixes some of the outstanding issues that have cropped up. This the bad stuff that's going to be fixed in the next version (updated sometime this weekend):

- becoming stuck after using upgraded Axii - fixed,
- no charm effect on enemy after using Axii - looking for the cause,
- wrong install directory of localization strings - fixed,
- overpowered Igni - fixed,
- need to reintroduce stamina regeneration cooldown after Sign use - done,
- fix roll/piruette direction while strafing - wip,
- add info about restarting the game, not using old savegames with the mod installed - done,
- fix typos in readme and translation - wip,
- scale dark difficulty down,
- tutorial, I'll probably leave it as it is.

From this thread