I've lived here since 1989 and have used one MMM and three different RFM's. I much prefer RFM's. Here are a few things from my experience in no particular order:
1. LandPride makes really nice, heavy duty decks. In a given width, they require a little more tractor than lighter/cheaper decks.
2. Variances (grass height, part of the mowing season, blade sharpness, ect) make it difficult to give you absolutes.
3. Raising or lowering my deck even 1/2" can make a difference on how well the rear discharge spreads the clippings.
4. I have an old Caroni side discharge deck from 1991 that has been broken, re-welded and resurrected several times and it will still cut anything. I recently wore my rain suit and mowed in the rain with it.
5. When we bought some adjoining land, we also went from a B7500 / 5 foot side discharge LandPride to an L3200 / 6 foot rear discharge landpride. The yard grew from 2-1/4 acres to 3-1/2 acres and the mowing time didn't change.
6. The B7500 had just marginally enough HP (21) to run the 5' LandPride because of hills. If our land was flat, 21 would have been quite sufficient.
7. The weight of the deck plays a big role. The old Ford 1210 with something like 16 or 17 horses handles the much lighter weight 5 foot wide Caroni with ease. When I tried the 5' LandPride on it, the poor old Ford was way too light and the mower deck handled the tractor. Dragging the heavier deck up hills while cutting overtaxed the little blue tractor.
8. My FEL is never on unless it's being used. That includes the frame and all.
9. Side discharge is nice for "raking leaves", but it forces you to mow in certain patterns - especially when the grass is taller - to avoid windrows. The last deck we bought is a rear discharge, and it's nice to mow in either direction along things that I don't want to blow clippings into.
Here are the three tractors I've used RFM's on. Took the opportunity to do a family photo when the L3200 was delivered. Sold the B7500 and kept the Ford just because it's handy. The first tractor was a Cub 154 LoBoy with a belly mower.