We got the Boru Croi Beag installed just before christmas and are delighted with it. We went for the inset to minimise disruption to floors, existing mantle etc and can happily say we are delighted with it. The reduction in draughts was incredible and immediately noticeable and it uses only a tiny bit of fuel to heat our room. The Croi Beag is only a 4kW stove so will not heat a massive area, but is sufficient for our needs.
I would just be a little cautious with regard to the installation. Our supplier/fitter had been out before installation, took a look up our chimney and basically said 'yeah it's all grand'. However, when they took out the existing fireplace and opened up the hole a bit more they got a better look at the chimney and told us that the existing clay liner was crumbling and so the entire chimney would have to be re-lined with a flexible flue. Luckily we live in a bungalow so only need 6m of liner.
I'm no expert or builder and wouldn't know what to be looking for so I had to take their word for it. Our house was built about 40 years ago, so the flue could well have been crumbling but we hadn't seen any other evidence of this recently. Apart from that, the installation was very quick and we’re very happy with the stove.