I have never owned one myself so have no personal experience to offer either, but from what I can gather Ram pickups have a good reputation for reliability. They should prove inexpensive to run too. The engines and transmissions are well proven and have been used in many different Chrysler group products, the Hemi V8s especially.
I think they're fairly straightforward to service, and shouldn't need specialist attention. Any good garage should be able to service it for you if you provide the parts (probably cheaper that way anyway). Chrysler/Jeep garages may be able to help too, but will be pricier. The previous genation Dodge Ram (2002-2008) was officially sold new in the UK in limited numbers for a couple of years (2005-2006 I think, but I could be wrong).
The latest generation introduced in 2009 have independant coil-sprung suspension all round instead of the more usual leaf-spring rear suspension. They handle relatively well for a full-size truck. 2009 model year they were still marketed as Dodge Ram 1500s, from 2010 onwards they are just Ram 1500s, with Ram becoming a brand in its own right.
I personally would have thought that you wouldn't need to import a Ram 1500 from the US as there seem to be plenty of examples in the UK already. You shouldn't find them too difficult to find in the UK. Check the classifieds in magazines such as Classic American and look at the dealer ads too. Have you done a search on Autotrader? Even late models may be listed as Dodge Rams on there.