What basic 4K switchers are you guys using. A single TV does not have enough HDMI inputs so I will need to switch 4K. I will need 4-8 inputs and only one output. What have you used and what caused the least headaches?

What 4K sources will you use?

You need to be looking at current model AV receivers in order to have multiple HDCP 2.2 inputs, and even then you'll only get 3-4 HDCP 2.2 4K inputs, unless you're going with something over 5 figures like Krell or Datasat.
There's nothing "basic" out there yet.
Prove me wrong, internet.

I've heard good things about the Zigen 4k HDMI switches. Haven't had an opportunity to use it yet myself.

[Link: zigencorp.com]

Make sure what you are spec'ing is the latest 2.0A models. If it isn't 2.0A they'll never get the best 4k image. You'll be missing something.

[Link: atlona.com]
[Link: atlona.com]

nowhere close to 5 figures

The original poster didn't say, so I assume he means the 4K with HDR and such. The one that takes 18Gbps.
Those Atlona switchers are only 10.2Gbps = which HDMI 1.4 specs can meet. And they even say they can NOT support HDCP 2.2

Ethereal has some new cheap HDMI switchers. They are only 10.2Gbps as well but at least they support HDCP 2.2
[Link: metrahometheater.com]

My experience has been that beyond 4x1 or 4x2 things get very expensive. Higher still if you need 60Hz. There may be some new products at Infocom. For the short term the most pratical solution might be two 4x1 followed by a 2x1. From a user control standpoint this solution is grim, but if there is a control system, the details can be buried.

Do you really need eight inputs in the short term?

Breaking the 10 G wall is currently not cheap or reliable.
This will change by CEDIA I think (or hope anyway), but today building a system around true 18 Gbps capabilities with anyone's switching hardware is suspect. If you need to do this today run "2" HDMI cable: one for the system and one for the higher bandwidth source.

BTW: Be damn careful about which/whose "18" Gbps cable that you use, the Redmere 17xx series product is at the very best "iffY" (this includes all of the brands out there claiming between 18 and 33 Gbps capability) and the 81xx series has been once again delayed. It is true that on it's best days, down hill, in neutral AND with a large diameter cable the Redmere 17xx series chips will nudge 18 Gbps, but even then rarely across all 3 video channels and then of course there is the lack of EDID compensation/repair.
[WARING: SELF SERVING STATEMENT]
The Ethereal Velox active cable up to 15 meters in length and the Ethereal MHX passive cable with the GA1 Gigabit Accelerator up to 17 meters in length will support the full 18 Gbps bandwidth. These products are as one would expect from us, DPL certified.

Beyond 17 meters you will need to look into fiber and by CEDIA you will see the capability to go over 300' at the full 18 Gbps (hmmm... I wonder who will have that?).