I went to Mayo just a couple of weeks ago. They put me through the testing wringer, but that's what I went there for, so I can hardly complain on that count. Here are my issues:
1) The physicians do not speak with one another.
I was getting parallel diagnostic tests for POTS and adrenal insufficiency, and the docs did not communicate. If I asked endo about POTS or neuro about adrenal, they'd give me blank blink-blink looks and say, 'that's not my specialty'. (But I'm asking you how it RELATES to your specialty! Did not seem to matter.)
2) The testing is sometimes horrifyingly painful.
I would not want to discourage anyone from getting needed testing, but if they hook your legs up to electrodes, RUN, do not walk, away. When I gasped and teared up and said 'I can't do it, I can't do it', the lady performing the test looked disgusted and began baby-talking at me. My next (far gentler) autonomic test, where they ran a low current down my leg to measure transmission (felt like prickles), both techs admitted they'd transferred over from that department because they couldn't take the pain their patients experienced. "It's torture," they said. Yep. I'm sure everyone has different levels of sensitivity, but the point is that horror and agony WAS the 'typical' reaction. Not only is that the case, but the attitude of the first tech made it seem like I should just buck up and take it or I was a child.
3) Some of the testing was unnecessary.
Looking through the tests that were done - and there are twelve or thirteen pages of results - is ridiculous. I sat down with an (excellent! amazing!) GP who, while not expert in ME is still very knowledgeable, and she couldn't make heads or tails of why they'd ordered certain things.
4) The physician quality varied wildly.
Take my endo - not super-knowledgeable, but sympathetic, kind, and willing to talk science - and one of my neuros - very knowledgeable, kind, and willing to talk science - and contrast them with the allergist I saw, who got numerous medical facts wrong about me on her final report (including the diagnosis I had so far!) and treated me so dismissively and rudely that I actually wrote a letter to Mayo. She denied I had "any sign" of allergic reaction, despite already having certain Ig results that directly contradicted her.
5) The tendency is still to be dismissive.
The default attitude of a doctor should be warm, accepting, and caring, not perpetually dubious with one brow raised. Even the endo who I generally liked didn't start from the assumption that I was actually ill, but rather had a generally open, yet "we'll see" kind of attitude, which only shifted once she had evidence SHE considered concrete: lab values. When I reacted poorly to cortisol, she assured me this was impossible, and also that cortisol is the only treatment for adrenal issues, neither of which is the case.
6) The tendency is still to be close-minded.
I thought that once I left my local docs, I wouldn't hear "but that's rare" as a reason to exclude a diagnosis. Or, "but you're too young to have cardiac issues." Yet... I did hear that sort of thing, and more than once.
The pros:
1) They will run whatever the hell kind of test you want, generally.
2) They operate like a well-oiled machine; appointments generally happen on time, and most doctors don't yank you in and shove you out the door. Instead, they appear to have actually budgeted a reasonable amount of time for each appointment.
3) They have every test on the planet available - even stuff like Total Blood Volume via spectroscopy, which is pretty cool in contrast to the injection of radioisotopes, which is how other hospitals do that.
So. There's my two cents. I admit, I wouldn't recommend it.
Edit - one more (important!) thing to add to the positive column:
4) Mayo is still VERY well-respected. Despite the fact that their standard of care seems to be dropping, the general public and most doctors aren't aware of this.
If you walk into the office of a new doc and you let them know you have this-or-that labwork, or this-or-that diagnosis and they give you the skeptical eyebrow of doom, watch how fast their attitude changes to respectful surprise if you can add "from Mayo Clinic". If the results are from Mayo, you can almost see them thinking, PERHAPS WE DON'T NEED TO DO ALL THOSE TESTS AGAIN. Halle-freakin'-lujah.
It's actually one of the main reasons I went there. I suspected that if I got a diagnosis from Mayo, no one would ever contest it. If I had irregular results from labwork done at Mayo, no one would insist on redoing it "just in case". They'd just accept the Appeal to Authority that Mayo's name/logo presents and pick up wherever Mayo left off. So I guess I'd say "if you want a diagnosis no one can contest, go to a place like Mayo."
Just be aware that it can work against you, too. If they hadn't found anything concrete, I would be up the creek without a paddle, and it's sheer luck that they did, because their 'diagnostic process' is pretty screwy.
-J