Rollers are good for occasional use. and like
Het Volk mentioned they have a very road like feel because you really have to pay attention to what you are doing. i've fallen off on more than one occasion. nice thing is they will hide quite nicely under a couch if doing in the living room.
i had them but got bored with them and moved up a few notches. but again, for occasional use they are nice.
ther was a set for sale on my local craig's list for about $120 with aluminum drums.