At this time, any one of the two cards that you can obtain.  Be it BB, Newegg, EVGA, MC, or other vendor.  The queues for both cards are very long here, but you will pay MSRP and not inflated scalping prices. Newegg has their shuffle and most cards are sold as bundles with other things; at BB and MC you'll probably have to camp out prior to the days they have drops.  Amazon you can forget as any cards they receive are purchased in milliseconds by bots and then flipped on Amazon by third party sellers.
 
Personally, I would use the queue system here and just be patient and wait, I am doing it that way.

In an ideal world, where prices are at MSRP, you should always go for the 3080 instead of a 3070 ti.
The card scores just above a regular 3070, if it was closer to a 3080 in terms of performance, then it could have been a reasonable option.
I believe that gap can be filled by the rumored 3070 super, but remains to be seen.