According to TechCrunch, Coinfloor is associated with a well known Nefario of GLBSE infamy, so personally I would not touch it with a 100 foot pole:
http://techcrunch.com/2013/10/29/coinfloor/
http://techcrunch.com/2013/10/29/coinfloor/
Quote
Also of interest is that, while the UK startup is founded by Mark Lamb and Amadeo Pellicce, one of its team members is James McCarthy (aka Nefario) who was previously involved in Global Bitcoin Stock Exchange, which controversially shut down last October.
This is already being discussed at:-
https://bitcointalksearch.org/topic/m.3435075
