It seems that 2 Expert Packs > 1 Premium Pack

I hope they're not lying about the higher UR chance, as this was not true for ME3. It was "higher" chance there because you drew from the same pools 2 times, and both had 7.5% chance for an UR. So it is higher chance in theory, but technically the 7.5% did not change in the Spectre pack. And the store in ME3 still says today it's higher chance for UR, but we know that is not true.

So I'll take what the MEA store tells me about premium packs with a grain of salt. So far out of 3 of them opened I got 0 UR's, so that's 6 failed attempts at drawing from a pool that is supposed  to be higher than 7.5% (from what was the chance in a ME3 Spectre pack).