I dont think PCI was a good choice on the A1200, I had the LT4 version and sure you could run a 1600x1200 WB, but running fast scrolling graphics on the Workbench was slower than regular AGA in 4 colors. For example, scrolling in Ibrowse felt laggy and this was with a 060 board. If you wonder what I am talking about, play a module in Hippoplayer and enable any hipposcope. Watch hipposcope run in slo-mo.
As I was told this is because of how memory is shuffled to the GFX-board on the A1200. I was told that on on a Z3 system this issue is gone.
Another nice detail about a loaded PCI system is that the Amiga will use around 100w if it is pumped to the max (PPC/060/Mediator loaded system).
None of those issues on my A4000. power is not a issue on the 4000 either,hence the 150w psu. It never made much sense to me to expand 1200's with all the bottle necks,and you still won't have zorro3. by the time you fix the psu,add a bunch of dongles, you have a semi reliable machine half the speed of a 4000. I can see why people are disappointed. You saved no money and its still mediocre at best.
Mediator is still a good choice for the 1200 i suspect if you want better gfx on the 1200 for browsing or such. there were virtually no other options, unless you use a zorro2 expansion and video card like picassoII,iv,etc. which would still be slow. Mediator also gives reasonably fast usb on the 1200 instead of those slow,silly clock port expansions.