Both good companies. The stoves are certainly adequate size for 1800 sqft even in VT. Both stoves are newer models but reviews so far have been very positive. I doubt you will go wrong with either of them. Some differences between the stoves:
- catalytic/hybrid technology vs. secondary burn: The F55 is a non-catalytic secondary burn stove while the Ideal Steel is a hybrid stove with secondary burn and catalyst. The Ideal Steel will burn cleaner, probably be slightly more efficient and allow a more regulated heat output and longer burn times which will be convenient when it is not that cold outside. For the F55 you will achieve less heat by loading less wood and potentially letting the stove go cold between burns which will result in somewhat more work overall. A cat stove has the disadvantages that you need to exchange the cat about every 5 to 8 years and you need to make sure to only burn untreated firewood and approved firestarters to not harm the catalyst.
- Woodstock sells only factory-direct while Jotul relies on its dealers to provide customer support. Thus, I would check if you have a Jotul dealer nearby that you feel confident with. Woodstock's customer support is consistently top notch.
- Installation: For the Jotul you will probably get the full package (stove, install, chimney if needed) from the dealer. The Ideal Steel you will need to install yourself or hire a licensed sweep to do it for you.
http://www.csia.org/search
- Design: If you will spend time in the basement and watch the fire don't underestimate how much the visual appeal of the stove will impact your enjoyment of it. However, the IS can be customized extensively while the F55 only comes in black.
- Hearth: Maybe not an issue for you since it is a basement install but the IS needs a hearth with a r-value of 0.41, the F55 is ember protection only. For both check whether their clearances are ok in the space you want to install the stove.
- Loading: The IS is a east-west loader (you are looking at the sides of the splits), the F55 a north-south loader (you will look at the ends). Most people think N-S loading is more convenient.
Regarding the basement install: Is the basement finished and insulated? Concrete walls and slab can take up a lot of heat. Plus, there is no guarantee that the warm air will really rise to the upper floors. It will depend on a lot of variables like proximity of the stove to the stairwell, possibility of the cold air upstairs to be moved etc. For some people a basement install works for others it does not and it can be quite tricky to pinpoint the exact differences.