As you said, this could create a big debate. I was told by an oil company owner many years ago that setting your t-stat back by more than 3 degrees at night actually burns more oil than leaving it alone. I peronally think it's more cost effective to maintain a temp constantly than to let the house cool and then try to warm it back up.
""Furnace/Boiler thermostat setback rant""
IF A BOILER IS PROPERLY SIZED, setting back saves money. You are having one long run (Instead of wasting fuel for every on/off cycle), you are heating a colder zone. (More heat transfer from hot to cold, = effiency gain).
If it is over-sized, you will still have many runs, possibly more then just maintaining the heat to begin with.
BTU is a BTU, if you can transfer more using the same amount, you are gaining effiency.
""End Rant""
I can't argue this with a pellet stove, because I don't have the personal experiance/knowledge to back it up.
The main reason you save money setting back with a boiler is, you have less starts, and every start wastes a little bit of fuel, and if it is properly sized, you will get one long clean burn, with no burner cycles.
With pellets however, if you run in manual room temp mode, and don't exceed your setpoint by more then a degree , I don't really see how you save much fuel cycling on/off, because starting up and getting to heat distribution mode will waste pellets. However, if the stove is off a good amount of time (This is the number I'm not sure of/don't know), then I could see how cycling off/on would save you on pellets. Likewise, setting back a good 8 hours, should result in savings either way, as you are heating a colder zone, and gaining more heat transfer.
IMO.
As for which pellet stove to pick... I think Jake summed it up well.
My concern is the room is quite small SQ FT wise, and will probably overheat quite quickly, even on a maintenance burn, and depending on heat loss, it might stay that way. If this is the case on/off might be the best route. I noticed you liked keeping the room @ 58*, do you keep it this cold to save money on oil, or is this your comfort range?