As an owner of a Daytona 675, I'd say the Striple is a cracking bike, the biggest differences between the R and the regular version is less power and rpm plus a more budget suspension and brake set up, however unless you're going to be hooning around at the bikes limit most of the time the std bike is probably all you'd need and a good buy - especially if it's a low miles rarely ridden example in good nick.
Bad points to look for would be the exup valve first and foremost, it's the only serious weakness the bikes have, but for a few hundred quid it can be removed and the bike remapped to suit. It gives issues by getting semi seized and jamming - causing the eml light to come on, however again there is a cure for spurious eml faults by way of a bit of freeware and buy yourself a cheap OBD cable - have a look at the Triumph forums for more info re "Tunecu", especially
http://www.675.cc" onclick="window.open(this.href);return false; where I know for certain you'll find all the info you could need.
Running a fairly distant second in the problems dept would be the cam chain tensioner, a nasty noisy vibe at somewhere between 6-10k rpm from the RH side of the engine would indicate the cct needs upgrading to the manual adjusting type.
Other than that they're pretty solid bikes, especially if they haven't been messed around with and haven't been neglected, good bike if you're getting back into the saddle tbh. Hth DG.