I am running a FATE campaign currently with a group that has a strong tactical history (D&D, RoleMaster) and I absolutely feel it strongly encourages roleplaying. My players do not first think "what powers / actions / skills will I use?" They think "what's in the area I can use" and "what aspects of the situation / personalities can I use".
Example:
In our first session, the players fought some wild dogs. They used terrain for cover, growled at the animals and did a few RP things, but mostly it was "roll fight / shoot" -- mostly tactical play, but definitely more RP than in other systems. However, that was not the big fight. Oh no; the big fight was a social combat that started entirely by accident ...
So, Hunter is not a good rider, and so fails his riding check, so I state that the horse is slightly injured and will need walking for a while [GM is trying to slow them down so they get caught out at night ...]. Jemima complains at him and I, as GM, notice she has an aspect "Kids nowadays don't know s**t", which I compel and she starts provoking and insulting Hunter. Hunter I also compel ("Chip on his shoulder; no-one thinks he's good enough") and they start fighting, doing some nice stress damage to each other (more than the dogs ever managed). Our Mechanic stays out of it, just watching the fight, but then the Scrounger, looking at his own aspect "Your stuff is my stuff" decides to "borrow" our mechanic's pistol, and only JUST succeeds in evading notice, so I rule that in examining it he drops one of their only three bullets into the grass. He fails to find it. So when the first two stop fighting, the next thing he has to do is be diplomatic and ask for help finding the lost bullet ...
I also find that creatures are more interesting; the use of aspects makes every combat different. I'm running a "post-zombie-apocalypse" game, and so far they've run into two types of Zees:
YER BASIC ZEE:
* Fight +3, Notice +2, Everything else +1
* Can move real fast when it has to
* Not the brightest
* A two point stress box, and a mild consequence slot
ZEE THAT USED TO BE A HUNTER
* Fight +4, Sneak +4. Everything else +1
* Better to be safe than eat
* Sneaky SOB
* Brighter than a dog, but just as fast
* 3 and 4 point stress boxes, mild and medium consequence boxes
Against a mob of the first type, the players could depend on keeping out of close range (I'd have to spend a fate point to invoke their speed) and 2 decent hits takes one down, so one player distracted them and lured a group off, while the others shot them from range.
The second zee (a solo attacker) ran away from them after first contact, then stalked them and when a single player was alone-ish, attacked. I might have had a hand in the being alone thing, as I compelled her to go out wandering to get some parts for a repair job she was doing ("I can make it better than it was before!"). It ripped her up well (new consequence "missing bits of yer belly") and was driven off, but not killed by the others when they ran over. Very nasty encounter. Later it tried to sneak up on them at night, but they had managed to find its entry point, were waiting, and fired at it. Even when I invoked the "Sneaky SOB" AND the situational "dark night" aspect, the party's sharpshooter, with the help of one round of aiming, his shooting stunt and some good dice rolling did some serious damage, shooting half its head off. It ran off and there was a tense moment as the shooter decided whether to use his last rifle bullet on the fleeing Zee. He did, rolled well, and with the penalty for missing half its head counteracting the Sneaky and Dark aspects (I invoked them both again as it tried to escape) he took it out. Much rejoicing.
The use of aspects is a critical feature -- they have three uses:
* They define fact: Yer Basic Zee is stupid. That is a straight roleplaying thing. Will they keep following a target when others are shooting at them? Yes, because they are "not the brightest"
* They can be invoked for game effects. Is the ex-Hunter Zee sneaking poorly? Well, I have a limited number of times I can boost that result because he is a "Sneaky SOB"
* They can be invoked to influence narrative. That's most usually done TO players (e.g. the social conflict) but can also be used BY players. If the players were losing to a group of bandits, I'd allow them to invoke the campaign's aspect "There are Zombies everywhere" to have a gang of zombies turn up just then and make the combat a three way fight.
I think that multi-facted use is the genius of FATE -- lots of systems do one or the other of the above three uses. But in FATE, all I have write on my character sheet is "I am tougher than anyone" and I have a roleplaying description, an advantage I can invoke when needed and a hook for the GM to get me into exciting situations.
It really works.