This may have already been covered in the thread, but is there anything in particular you need to do to allow multiple AP-handoff? I've replaced some old unifi APs with these, and although two access points seem to be playing nicely together, I've been seeing some lookup delays which I'm unsure are related to the APs or something else. I've given both APs the same SSID and password but otherwise have basically the same setup as michaelmurfy, except I've enabled the 802.11r fast roaming profile.
I also see that a few of you have set up both 5Ghz and dual band wlans - what is the advantage of this?
While bandsteering and having the same SSID for 5Ghz and 2.4Ghz is alright at segergating clients to where they should be, its not perfect. 5Ghz clients DO end up on 2.4Ghz.
In some cases you wish to have a 5Ghz client on 5Ghz Only, in this case its handy to have a 5ghz only network to jump onto. Same goes for 2.4, if a 2.4ghz client only client tries to join a bandsteered network, its going to have an issue for the first few tries.
i find roaming just helps hand things off more smoothly than allowing clients to just do it all themselves. I have used ERoaming more for controlling clients too far away rather than forcing roaming as its kinda a brute force approch.
I take it a step further, having my becon timings to encurage more uptake of 5Ghz, extra channels to force an AP.