I have both but as others have stated, really depends on what you are using to do. I find myself using the track machine if I need dozer like characteristics and the wheeled one for running around moving stuff quickly on good ground/hard surfaces. Never thrown a track or had a flat tire (foam filled) so I cannot attest to how hard to replace either would be.
Bottom line, I use the wheeled one the most but if I could only have one machine it would be tracked, it can do all the wheeled one can and some work the wheeled cannot. It just costs more to buy and for the average homeowners use, I do not think you will burning up hours/tracks very often so I think upkeep would not be a major difference.