Shane, I beg to differ, a S150 should be indenticle to a 763, A s130 would be next smaller as its the old 753. And now the S150 is available with the turbo motor and classed S160 if you want more power.
The S250 is a 2500 lb rated lift machine. Between the two for me it would depend. Do I intend to lift anything that heavy? Do I need hi production to do alot of some task? Both are pluses for the s250.
However if you need to move it with a 1/2 or 3/4 truck, need acess to tight areas, need a lighter footprint on your lawn, I'd lean towards the smaller machine as it will do most everything the large one can just at a slower pace.
It sound like you a homeowner class uses and most people around the house don't need a machine like a s250.
Remember the rated lift capacity is 1/2 of the tipping lift, so even if the s150 is ratted 1500 lbs, it can pick up 2500lbs with a areful operator, and the s250 can lift @ 4000 to 4500 lbs
Now if money was no object would I get both, maybe, would lkely get a T200 or simular track loader instead of the s250. But thats me
Ken