As you have gathered by now, depending upon who you ask you will get differing recommendations as to which TLR to go for.
Your heart seems set on a Rollei of whichever type, but if image quality concerned you, then there would be little to differentiate a 'cord from a 'flex using the same lens, be it a Xenar or Tessar. However, a later 'flex with the Planar or Xenotar would yield superior image quality, but inevitably a 3.5E or 3.5f model will cost more.
To touch upon comments already made, the lever wind of a Rolleiflex is easier in use, and film loading is automatic. The film backing paper is fed through two rollers and attached to the take up spool, and then the back is closed. One then simply winds the lever wind until it automatically stops, at which point the film is at frame 1. In the Rolleicords, and possibly other non-Flex models, after attaching the film leader to the take up spool the film needs to be manually wound to line up a marker on the backing paper with a marker on the camera film gate, then the back is closed. From thereon, winding to the first frame is the same as on a 'Flex.
If you find one within your price range, and you've no wish to consider anything other than a Rollei, I would definitely go for a late 'Cord or any 'Flex that has interchangeable viewfinders and screens. I believe you will be somewhat disappointed in the lack of brilliance with the standard viewing screen and fitting something like a Beattie Intense screen will transform what you see.
One consideration is that a 'Cord is unlikely to have been subjected to professional use, as is more likely with a 'Flex. Also, you should try and get to handle one of each before you buy. You may find this will sway you one way or the other. A simple test, and one you should not ignore, is the lens focusing panel should move smoothly. If it feels rough, or "notchy" in any way, give the camera a miss as this is likely a good sign that the camera has suffered a substantial knock.
Mention, has already been made of Yashica and Minolta. A good YashicaMat, the original plain model without meter, and especially one fitted with a Yashinon lens, is every bit the equal of a Tessar/Xenar equipped Rollei as regards image quality. This was my introduction in 1963 to quality imaging when I purchased it new, and I still have it. Unfortunately, my comment about the professional use of a 'Flex can also apply to the YashicaMat as it was often a back up camera to the Rollei, or indeed the main camera favoured by wedding photographers. The Minolta Autocord with its Rokkor lens is equally good as regards image quality. Both of these should cost you a lot less than a Rollei.
A small note about the Mamiyaflex. The C330 is indeed a far more versatile camera than any Rollei TLR, and the 5 element Sekor f2.8/80mm is every bit as good as the equivalent Planar or Xenotar (5 element versions) but its weight mitigates its use for hiking. I've just weighed my 3.5f with waist level finder at 1220gms. My Mamiya C330S tips the scales at 1700gms.