I did 4x4 rounds for a couple of years and I found it to be more work almost. The baler is so slow unless you have netwrap, you end up stopping and sitting tying. Then the bales are only 400 lbs or so, so you end up with a bazillion of them to move off the field.
I don't think I'd do rounds smaller than 5x4 or preferably 5x5. I hate the tying!
That is an interesting perspective and one I never looked at, however, we do 4-4's for horse people and the Amish because most horse people don't have the equipment to handle larger bales. A small CUT with a FEL will handle a 4-4 as will a small bobcat skid loader. The bigger ones, 4-5 and 4-6 need proportionately larger equipment putting them out of reach of the average equine customer and most equine operators want 'idiot cubes' becaue that's what they are set up to feed.
My wife's Percherons have always been fed rounds, the larger the better. I roll 4-6's in net for my own use, some rounds in the excess of 1500 pounds, but then again, that's beyond the capabilities of most people to handle. You need the equipment or you are S.O of Luck with large rounds.
I've tried (unsuccessfully I might add) to convince my largest contract customer to go to rounds. The raise Alpaka (sic) Lamas for the wool, which I understand is worth quite a bit. I even offered to make them custom round bale feeders (which I use to keep the rounds off the ground and limit waste through controlled feeding) but no dice. They want idiot cubes and I oblige. It sort of pains me to spit a thousand on the ground, knowing they have to pay a crew to load racks and fill their barn (I did, out of sympathy, loan them my Sno-Co bale elevator on a long term basis as I don't use it anymore).
Personally, I don't much care if it's net or twine (has to be net on clover over wheat straw) because cutting the twine is as easy as pulling a net wrap at least for me. I just run my box cutter dowm the side of the bale, grab the twine and pull it off. Takes about 15 seconds or just as long as pulling a net weap.
My bales feed at basically chest height in custom designed feeders with roof's and a large swing door to load the bale with the forks (eye to the sky). Pull the net or cut the twine, close the door and latch it, drop the feeder bars and let 'em eat.
My big gripe with rounds was how much forage was wasted. The ground contact plus the weather (rain and snow) caused an appreciable loss in forage and consequently wasted income. My feeders eliminated all the waste due to spoiled hay. I cut my consumption by a third.
Before, in the spring, I had a layered buildup of spoiled, rotten, moldy, peed on hay at every feed station. Now I have none.
Klene Pipe Structures in Indiana makes a feeder similar to what I made if you are interested.