I had a MF1643 cab geared tractor that I traded for a MF1754 HST hydro tractor. The difference is power was quite noticeable! So, I went from a 43 HP geared tractor to a 54 HP HST tractor. I'm almost at 200 hours on the MF1754 and have yet to find anything that this tractor struggles with power wise in terms of compact tractor use. It is not going to pickup a 10,000 lbs. log. I've moved a lot of snow, dirt, wood and stone with this tractor. No issues. Mow, plow and loader work with it, no issues. I've had some other issues but I think that they are specific to my tractor. You can see my threads if interested.
Here are examples of power difference/loader capability. Had a pretty good size rock (3'x3'x2') on my property, couldn't pick it up with the MF1643. So, I ended up pushing it out of the way. Working on the trail again and needed to move it. The MF1754 picked it up pretty easily! Also, the MF1643 would struggle moving large piles of iced up snow. Would have to take smaller bites with the loader or it just wouldn't pick them up. MF1754 handles them with ease today. As a note, I had the MF1643 checked out twice by a dealer and they verified that it was functioning properly. So, it was what it was.
I had a Massey dealer tell me that the MF1643 geared tractor was equal in power to a MF1754 HST tractor because of the HST transmission. I have not found that to be true.
These are approximates when comparing the MF1742 to the MF1754. The MF1754 weighs 500 lbs. more and has a 6" longer wheelbase. Weight and longer wheelbase are all plusses for getting power to the ground and stability. Also, more lift capacity at the three point (500 lbs.) and loader (600 lbs.) with the MF1754.
It all depends what you are using the tractor for. IMHO, the MF1754 would win out over the MF1742.
You might want to do a search of threads on this forum as some owners of MF1758 HST tractors have reported issues with HST power. Also, forum member, onceacop, has some excellent writeups and reviews of his MF1758.
Good luck with your decision.