I had the same dilemna as you . . . the Shelburne or the Oslo. In the end I went with the Oslo.
My specs: Heating approximately 1,800 square feet (Cape) with moderate insulation (three 2 x 4 walls with fiberglass insulation and one 2 x 6 wall with fiberglass insulation) using a mix of mostly hardwood.
The stove: I typically run the stove between 500-600 degrees F. I have on occasion (twice) accidentally let the stove go up to 700 degrees F.
My opinion: I would buy this same stove in a heartbeat . . . or maybe one in a blue black finish for a little more bling than my traditional matte black finish (although the matte black means I can easily spruce it up this Summer with some stove polish). The Oslo is a heater -- plain and simple. I think it looks good, but more importantly to me it produces heat which is why I bought a woodstove. Originally I bought this stove thinking I would use it to supplement my oil boiler when oil prices were sky high . . . figured it would be good for weekend and evening fires. Foolish me . . . I have pretty much used this around the clock . . . and the fact that my oil tank has dropped from 3/4 of a tank to a point about halfway between 1/2 and 3/4 mark on the tank level indicator shows it.
As I said, I use this now as my primary heat source . . . although to be fair I have a small electric space heater in my mudroom/guest bathroom/utility room . . . since my oil boiler rarely comes on (unless it is really, really cold, when I'm lazy and haven't refilled the firebox overnight in middle of January or in the shoulder seasons) I use the space heater to keep that room (and the water pipes) warm . . . kind of odd if you think about it . . . I'm basically running a heater to keep another heater warm (well that and guests seem to hate sitting on cold toilet seats.)
I have never been cold with my oil boiler (thanks to hot water baseboard), but I will say the Oslo really pumps out the heat. It is truly a workhorse when it comes to producing heat for a wide range of temps -- from using it to warm the place up in the mornings or evenings in the shoulder seasons or to really keeping it warm in the house when it's 20 below zero and the winds are howling (although on those days I sometimes wish I had the larger Firelight as you can see the Oslo is really cranking.) As Peter said it easily puts out 3-4 hours of meaningful heat in the dead of winter and during this time of year you can get the fire going in the evenings and let it die overnight . . . and the house stays warm until the morning at which point you can easily get it going again with the coals in the firebox.
Originally I was thinking that I would have to shut off my upstairs bedrooms and bathroom . . . but I have discoverd that the Oslo puts out more than enough heat to warm up the whole house with the exception of the aforementioned mudroom space. I do occasionally use a fan to help move the heat through the home . . . typically in the dead of winter.
The only negative I have witht the stove is the ash build up in the front of the stove which dumps out everytime I open the front for cleaning . . . well that and the realization that and the manufacturer's definition of burn time is quite different than my definition. On the pro- side I love the simplicity/reliability of the stove (the main reason I went with this brand), side loading door, ash pan, large front viewing window and close clearances.
As I stated earlier I also looked at the Shelburne and the Pacific Energy T6 lines. I liked those stoves as well, but opted for the Oslo since the reviews here were overwhelmingly positive . . . plus when I asked more than one dealer selling multiple brands they all said the same thing -- the Oslo is one of those stoves that is built well with few repair issues typically. Not to start any brand bashing, but one dealer said once he sells an Oslo he typically doesn't hear anything from a customer for several years until it is time to put new gaskets in the stove . . . and that he felt the baffle was less fragile than the one in the Hearthstone line . . . again, not brand bashing, just repeating one dealer's own opinion.
This said . . . if you have truly narrowed your choice to these two stoves . . . based on what I've read here from owners of both brands . . . you should be good with either one.
