As a very happy and contented Canon user, I added medium format, I now have both and understand the good and bad of both. I went with the Mamiya/ Phase 1 option, this I considered the better option. It’s easy to get started on a budget, go to eBay and check out a Mamiya 645d [i, ii, iii] and a used ZD back or other. This option cost me A$4,800.00, the shots are fabulous quality, however, not suitable for sports or grab shots. Medium format is a dog to lug around; I use it mostly for studio work.
I elected not to go the Hasselblad route, the newer ones have a propriety digital back interface and you can only use Hasselblad digital backs. With the Mamiya/ Phase1 solution, you can use many available backs i.e. Mamiya, Leaf and Phase1; there also are others. Check out eBay. I am a long time Mamiya user (46 years) and have resurrected my RB67 Pro SD and lenses, my ZD digital back with an adapter mounts on the RB67.
I like the system so much that, I have just upgraded to the 645 DF body and soon a DM back. I have modified my Horseman view camera to be able to mount my Mamiya 645 DF body + ZD digital back and my RB67 KL series lenses. This system is a beast but, fabulous Macro shots with much swing, tilt and shift, also the best solution for panorama stitching.
5Dii, + L series, G9, EOS M, 645i, 645 DF + Mamiya lenses, RB67 Pro SD + KL series lenses, Horseman view body.