I have a 2810 HST with a 3375 hoe on a sub frame. If you are going to be doing much backhoe work or loader work you might want to look at the HST. It is a lot easier on the operator.
Also look at the area you will be digging. The sub frame for the hoe on the 15 series is under the tractor and the sub frame for the hoe on the 10 series is beside the tractor frame.
I had a new tractor with the sub frame under the tractor I used for a while. I didn't like it after using my 10 series
Both the Mahindra tractor series are fine, but for me the Dayco Hoe on a sub frame , and the way they mount and come off make the 10 series shine for a small hoe.
Look at both tractors with the hoe on them and check your ground clearance. Then ask yourself if you want to be dragging a hoe that low to the ground around on a construction sight.
And it is not just the 15 series Mahindra , I don't like any of the Hoes that the sub frame hangs down under the tractor.
I'm over in the Claremont area if you would like to try on out.
Dave in NH