I have given this quite a bit of thought too, as I consider which way to go with my next purchase. I am in the middle trying to decide whether to get a larger tractor (6xxx) first or a smaller subcompact or X7xx riding mower. Obviously buying the smaller tractor at its lower cost delays purchaseing the larger tractor for a much shorter time than doing the reverse of getting the large tractor and waiting to buy the small unit. So, I have had to consider what assets the small tractor has that I really need.
For landscape work I find the subcompact tractors are not as good for mowing as the X7XX riding mowers. For suburban yards both of these small units can fit where the larger tractors can't go. Having the small tools can really help lower the amount of labor needed to do finish work. The ability to do any real dirt work with these small tractors is limited, though it beats doing it manually. I am hoping that a small tractor/riding mower will be able to fill in the tight and close spaces that the larger tractors have trouble with.
A subcompact tractor is much better for instance tilling, landscape raking, pine needle raking, in a small yard with lower branches than the larger tractors. Given enough time you can get alot done with these small units. I would bear in mind that they are small and limited in their abilities to perform jobs which require alot of tractive force. For the larger jobs there is no substitute for a heavier tractor. Trying to force a small subcompact to perform the tasks that are normal for my 4520 or larger will yield poor results and take a long time to accomplish.
FWIW, I am considering the progression of using the X749 mower, 4520, 110tlb and either a 6115 or 6430 to cover the bases. I would still keep the small gas trimming mowers and tools but sell off the older 820 and 3030LS. I mention all of this to demonstrate one of the lessons learned over the years having owned a number of different tractors. That is the 8 in 1 tool problem, trying to make one model do it all, doesn't work out very well. I have often mentioned here on TBN that I don't want a fel in the way on my tractor so having the tlb as a separate machine is a real benefit IMHO. I reserve the right to change my mind at any time though.:laughing:
For those people trying to decide between a larger riding mower and a subcompact tractor it can be a tough choice. I would recomend you really think about your long term needs and uses, that is "what is the primary task going to be for the long term" to aid you in the decision process.