Versus mode imho, is not BAD...but it is not everything it could be, its definatley a lot of fun but also extremely frustrating and predictable.
I highly dislike the Slayers mode as unless you are using the likes of STARS Wesker or battlesuit Jill, you wont have much of a chance and will probably spend most of the time dead or playing catchup.
However that being said, Survivor mode is a blast, no matter the choice of character, the mode is a level playing field...the combat is fast and fun, and no weapon is ever considered "useless" not to mention there is less frustration to be had when bosses come along compared to Slayer mode, as people tend to avoid it rather than kill it, as the bosses can make a useful "distraction" especially the reapers in the mines.