Help me decide on first turntable purchase

Are you fairly sure you will stick with Vinyl, or just wondering?

I would add VPI to your list.  Of the ones you mentioned, I would go for the Mofi Ultradeck.  I had a Music Hall 7.1 and it is a pretty decent table with good isolation and a good arm for the price point.  I've never had the chance to do any serious listening to a Rega, so I'm not saying that I've listened to that table and prefer the others over it.

The phono stage is important, don't skimp on that.

If you can avoid making a purchase for an extended period.
I suggest selecting a few Albums that have impressed you from the digital collection and see if these are available for reasonable money as a Vinyl Purchase. 
To get the maximum value of the Vinyl as a source media, if these can be cleaned for you, it would be worth the small additional investment.
Both yourself and any owner of equipment being demonstrated will appreciate recently cleaned LP's   

From that point on, it will depend on how many demonstrations you can arrange for a Vinyl Set Up within your budget. 
My thoughts are that if you stick close to your Budget with New Equipment you will be more impressed how a Digital Source SQ Compares.
If you are looking at having demonstrations of used devices that were once over your budget, there is a good possibility that the Vinyl Source might be able to show the attractors it is known for over the Digital.

 As an initial experiment and re-introduction to a Vinyl Source,
acquiring a few Albums is not too expensive and the arranged demonstrations could introduce you to a new friend who is kept in contact with.

If  $3k is total budge of table and phono stage, consider  the $130 Schiit  Mani. 

This is based  on taking a personal demo with the Mofi thru my PL.  The Ultradeck is a a good value.

Best future upgrade is a decent LOMC then a $2-3K phonostage. It will take your LP playback to another level.

Only you know your situation, where the table will go, how you want it to sound. Rega are light and fast. Clearaudio even more fast and lean. VPI go the other way, MoFi, Music Hall sort of in the middle. How much you like the looks can sometimes matter as much as sound. This is fine because there is a lot more difference between carts, phono stages and arms than tables. Hate to generalize but this is a tendency. 

Then in terms of what you get don't forget that what you put it on is almost equally important. Especially if you go something light and stiff like Rega, you will want a really nice platform for it. But not just Rega, they all benefit big time. On the budget end you have Nobsound, while on the top end Townshend. In between lies a no-mans land of stuff that costs a lot more than Nobsound but not near as good as Townshend. Either of these are so good as to be almost mandatory equipment. For the table and the phono stage too by the way.   

Keep all that in mind then. This by the way is almost exactly the advice Michael Fremer gave me 30+ years ago. Didn't tell me what decision to make. Helped me understand how to make my own decision. Hope this helps you too.