Dirt,
the utility of the 3PH remains unimpaired with the addition of the subframe. Naturally with the BH90 in place the 3PH is unusable but after the very easy BH90 dismounting the versatility of the 3PH is completely regained. There is a loss of ground clearance, the subframe hangs low, but I haven't found this to be of any hindrance.
The mid PTO is another matter. If you use or intend to use any implement coupled to the mid PTO you are in for a dissapointment. The sub frame negates use of the mid PTO entirely, it gets in the way of the implements.
I believe, may be wrong, that the presence of a loader is required to use the subframe since these items are completely tied together for maximum resistance to deflection.
The foldable ROPS is also required.
The BH90 will toss the tractor around on occasion and there will be times when the contents of your scrotum will take quite a slam back down onto the seat. I can't imagine a non subframe application would survive for long.
There have been some previous instances of BH90 self-destruction reported here on TBN. As hard as I have tried I have not been able to duplicate those type of failures.
Expect to pay somewhere around 7 big ones (retail) for the complete installation including the bucket of your choice. That's a fair amount to be able to help your neighbors save a few bucks, but the independence provided is priceless.
Pay attention and observe all precautions.
I fully endorse the use of hearing protection of some type, I use the little green plugs, and eye protection is a must when pulling up any kind of root, they can whip dirt at you.
If you currently have a trailer you need to consider the extra length and weight the BH90 constitutes.
Best of luck,
Martin