I ran a RoadRat for ages and ultimately only really sold it because it didn’t really work for me with drops. As a flat-barred road bike it was fine.
Not the lightest thing out there and the fork was harsh – the carbon fork off the X would make a nice upgrade – but it was comfortable and pretty versatile in that you could run it with discs or vees, singlespeed, geared or Alfine and it’ll take anything from thin road tyres up to fairly substantial cross tyres and even thin 29er ones at a pinch.
Mine did a lot of miles as a winter training road bike, general hack and on easy bridleways with cross tyres fitted. Apart from the harsh fork, which you only really notice off road, the other thing people criticise is the slghtly faffy rear drop-out system, which uses a sort of combined derailleur hanger/chain-tug thing and means you need to remove the rear QR completely to slide the rear wheel out. I guess if you’re someone who regularly removes the rear wheel, that might be irritating, but mostly it’s no big deal.
I haven’t ridden much else in the flat-barred road sort of genre, but unless you’re really bothered about weight, the Rat’s great in a slightly retro, steelish sort of way. Hope that’s some help.