My .02
I have a 2305 with a 47" blower (since 2005), just traded in a 2.5 year old 3720 with the 59" Front blower. Both do a respectable job. The 2305 is very noisy but works well. I had the impeller ride up once. Decent downforce, not much lift height. Throws snow like a champ. My impeller is steel.
The 59" was quiet and worked great. Lifted very high. High enough to bend the adjustment pin on the mini top link. Decently rugged, probably weighed 350-450lbs without the A-Frame. Was about 5K in stuff when I got it, I think around 6K now if you buy it all now(blower, A-frame, front PTO kit).
I just got a 4720 (traded the 3720). Thought about the 76" Front loader mount with the rear power pack (Basically a skid steer blower with JD mounts). Pretty rugged (Saw one), weighs about 850lbs, I don't know if that included the rear pto hydraulic pump.
Downs: $9,200 retail :O). Can't put anything on the rear. Did I mention $9200? I could
almost mount a used 2305 with a blower on the front for that much $$$
Although I did think about it I ended up getting an 84" Frontier single screw unit. I'm not sure if retail was $3500 or that's what they charged me but it's substantially cheaper than the loader mount and just by weight (it's about 1100lbs) and impeller diameter alone it's a lot more rugged than my old 59 and more rugged than the pretty rugged 76" SS.
We haven't got enough snow to do it justice but I've 'played' with it. Yes, I'll miss driving forward - How much I'll tell you after using it for a while a couple of times times, but I don't think I'll miss it $5700 more (Actually the dealer would have let me have it for $4200 more than the 84")
Ups: I still have the loader, I can drop it in a heartbeat (in fairness I could have dropped the loader mount in a second also).
Anyway, I'm getting long winded. One last point. Lot's is made of the blower being wider
than the tires. I ran 6" extenders on each side of my 3720 with R3's so i was running 66" wide in the narrow position with r3's. Did it ever bother me being 7" wider than the blower - in 2 winters - No. If there was ICE I would ride up but I wouldn't blow ice anyway so I didn't care. I would usually just pack the snow under the tires. Then I could do a final pass on the edge if that 1 or 2" of compressed snow bothered me. Do I prefer it wider - Yes (Now I'm running an 84" blower on the 4720 with the tires at 74" (narrow).
Anyway, in my opinion here is my summary:
Convenience: Front mount wins
Comfort: Front mount wins
Versatility: Rear mount wins (loader mount the exception)
Ruggedness: Rear mount wins
Resale: Rear mount wins (more of a market to sell it to)
There are also rear pto mechanical front mounts that have a sub-frame that go under
the tractor but those are around 8-9K also.