If you want a lawn mower buy a lawnmower. If you want a tractor buy a tractor....not a part time lawn mower.....aka tractor with a semipermanent mower. Also the smaller HP tractors have short lift arms due to their proximity to the ground. Don't expect to do much (size or weight) lifting with a 15 or 20 hp tractor.
A 25 hp tractor with front end loader is a real handy to have around the place second set of hands...I have a LS 25 hydro. with front end loader. If you want to mow with it get a 3 pt or drag type mower so that when you aren't mowing you can easily detach it and it's not in your way to do other "tractor" things.
Other BIG deal is that in the spring multiblade turf type mowers get hung up in the blade area with wet grass. Getting it out is a PIA. If you have a tractor with a detachable mower rear mounted, first of all unless it's the turf kind with 3 blades it doesn't clog. If it is of the 3 blade variety, you can detach it from the tractor, turn the tractor around and with the front end loader (FEL) lift the mower easy peasy and wash out under it and when finished its out of your way for your tractor to be used for tractor things.......think hard about what I said......you won't be sorry.....Oh remember the money you spend is gone forever....what stays with you is what you bought with it......food for thought.