> Compared to what?
The Surface uses 15W U-series, so they can only be compared with the 13" nTB, the other two use 28W and 45W with dGPU, they're in entirely different classes specs-wise.
> Surface i5, 8/256 $1299, MBP $1499 or $1799 depending on the i5 processor.
1799 is an i7, so no. And the MBP has a graphical edge (50~80% better graphical performances) as it gets an Iris 540 to the Surface's HD 620.
> Surface i7, 8/256 $1599, MBP $2099
1799 (nTB MBP with i7), Surface gets an Iris 640, the direct (and almost identical) successor to the 540.
> Surface i7, 16/512 $2199, MBP $2499.
2199 (nTB MBP with i7, 16GB RAM and 512GB SSD).
So the Surface is slightly lower-priced, at least at the low end, but with the caveat of flexibility: you can get a 16GB RAM or 512GB SSD nTB MBP for 1699, for the Surface it's 2199 or bust, and you can cut the i7 from any nTB configuration at almost no loss[0] to save $300.
[0] https://ark.intel.com/compare/91156,91169 the only difference is 400MHz base frequency, 300MHz maximum turbo