Is Rega the easiest turntable to set up....

Rega tables are likely the best plug and play, particularly if you buy their cart. It is tricky however with other carts as some don’t have VTA adjustments. I must agree with some of the comments. It would not be my only criteria with a 4k$ budget. I personally bought a P10 last year and put it in sale the week after. You get a better table at this price point IMHO and a good audio store will be happy to demo and set it up for you.

Rega  has a particular sound compared to others . So listening test is important

I have Rega NAIA with Apelion2 and I use it as casual TT . I purchased it as it is simple to set it up- No fuss always ready to play- Plug&play

I mostly use Clear audio innovation TT with Davinci cart

and that’s what I enjoy most- letting to instrumental-jazz-vocal

Hope you get chance to go to dealers and listen to different TT

@lewm that is simply not true. The whole concept and science behind Rega turntables is that mass doesn’t reduce vibrations but transfer and store vibrations. It’s quite easily proven. Low mass and extreme stiffness does. Simply throwing more mass at the issue is not the solution. Read up on the science.

There are a ton of TT's that come mostly pre-setup. 

Pro-Ject

Techniques

MO-Fi

That's just off the top of my head. Think if you go to any local Stereo store, they will setup the TT for you for free if you buy from them. My local places will do a free setup if you buy a new cart from them. Really most new standard style TT's are not overlay hard to setup, if you have the tools, with a little knowledge they only take 30-1hr to get dialed in. 

For instance, my Pro-Ject TT took about 20min to get running from unboxing, when I swapped carts on it, took about 45min to dial everything in. But it was my first cart swap, being paranoid to mess it up, rechecked everything several times. 

The OP can probably see there are many ways to approach his desired outcome.

"I’ve pretty much eliminated the P6 but am also looking at a MOFI"

Even the highest level Rega, it still is a polarizing brand.

Having demoed the Mofi Ultradeck in my setup 6 years ago, I heard it as a "okay" piece for the price.

Now that it’s at $1500 retail, with a $500-1K whatever cart it can be nice setup for less than $2500. With a used $2-3K phonostage it will be a decent rig until a more substantial cash outlay for a used $5K table is desired. $3-5K used can get a noticeably "better" performing unit-IMO.