I agree with both Dayclona & challenger70.
I've dealt with both companies. (though I admit it was several years ago, nothing recent.)

Just Dashes does good work and has a solid reputation. I'd probably choose them first if I was building anything except a 1970 E body.

The reason for that is the name script on the right end of the dash pad.
In the past, I know that there have been issues with whether or not either company was allowed to include that script on the new dash pad. Some pads were received with the script separate and you had to find a way to attach it yourself. I'm hoping that they have these issues all sorted out now.

That script was originally chromed plastic, though the chrome wore off quickly through the use of cleaning chemicals on the dash. As far as I know, Dash Pad Pros (Ultimate Rides) was the only company making the script chromed, so if that feature is important to you, then you only have one choice.
(I guess you could try using silver paint, but it really doesn't look the same.)

Dash Pad Pros was slow and very hard to get in touch with, so going through eBay is a great suggestion. They use original metal dash cores, but they made my AC dash pad from a non-AC core and I had to file the holes a little bigger to get the AC vents to sit down flush into the pad like they should. That was a little tedious, but nothing that's noticeable once the vents are installed, and certainly better than testing their customer service.

Another thing to consider is whether you need a colored dash. I think Dash Pad Pros dyes their black pads to other colors, but Just Dashes might actually use colored vinyl. It would be a good idea to ask if you need a colored dash.

Tav