So, a few games have used the new movement rules, though in one they didn't get used as there was no fighting!
So far, the following seems to hold true (though this may change with further playtesting).
* Over all, the players get more freedom, and can create better tactics on the battlefield. This actually makes combat move a little faster.
* The number of opportunity attacks increases quite a bit, which you might think would make combat longer, but actually, with the additional damage being dealt, shortened it.
* It is important that people have any interrupts or reactions to OA's ready, otherwise they could potentially bog things down!
* Skirmishers become a real nightmare! Already blessed with masses of movement, as well as many powers that grant them mobility, they can tear into battle and out with relative ease. You need either good defenders or a good controller to lock them down (or at least, someone with good ranged attacks), otherwise you are going to struggle (evil laughter).
* Strikers remain the best at moving about! One of the largest fears amongst my players was that the strikers would lose their "thing". However, truth be told, they remain able to move out of threatened squares without provoking opportunity attacks, and like skirmishers, often gain additional moves, which give the increased mobility when compared to other character types.
* Defenders have to make some tough decisions. Often, if they don't stay put, they do not fill their role. Also, they have to decide whether provoking an opportunity attack is worth it (and with some brutes, it really isn't).
* Combat ran faster! In truth, it did. This was partly because Opportunity Attacks whittled away the enemies hit points, and partly because characters could close with enemies (or move out the way of allies) more easily. Battles where the new rules have been used have been about 25% shorter than I would normally expect.
I'll give you more updates when we have used the rules a bit more!