046, I'd love more details on this custom insert - website or contact information for them. Sounds interesting.
Seventyss, I recommend checking ********** for a wealth of information on this topic. They even have a ratings section for wood and gas units, so you can see what owners think.
I have a Quadrafire 4100i insert, heating most of a 2,600 sq. ft. house, and I am quite pleased. A blower is mandatory for an insert, in my opinion. I would also prefer a stove but if you have a masonry fireplace an insert might be the best bet. If you have enough hearth or a large enough fireplace then a stove might be mounted in or in front of the fireplace opening. I love the idea of soapstone stoves (Hearthstone and Woodstock stoves), but other quality stove and insert manufacturers include Lopi, Regency, Quadrafire, Napoleon, Jotul, Pacific Energy, etc. If you want long burns nothing beats a large firebox so keep this in mind when shopping.
A full liner is not too difficult to install if you are good on a ladder or your roof pitch is not that great.
Good luck.
Mark