I went to the manual to figure out how to change the autofocus modes, and it was there that I saw that the autofocus performance was dependent on the lens in use. Canon identifies 8 autofocus performance 'groups' (A-H), followed by a list of canon lenses and the group it belongs to.
Group "A" uses all 45 focus points, and the center point is a double cross type.
Group "B" is the same as A, sans the double cross point
Group "C" has 45 points, but the outer 10 points are not cross type, if I interpret their terms correctly
Group "D" has 45 points, but the outer 30 are not cross type, e.g. only the center section points are cross-type
Group "E" has 35 points by losing the outer 10 points entirely
Group "F" has 35 points available, fewer cross type
Group "G" has 27 points
Group "H" has one point only.
So as I read about that I thought that I might be in for a disappointment as 2 of my 3 lenses are not Canon and perhaps would not be well-supported. I don't know where my Tamron 70-200 fits, but I can confirm that I'm happy with the results so far. OK, so a few examples for the lenses:
Group A: EF-S 17-55mm; primes 2.8 or faster; EF24-70mm (both types)
Group B: EF24-105 f/4; EF70-300
Group C: EF75-300, 100-300
Group D: 24-85, 55-200
Group E: 35-70; 28-70
Group F: 22-55
Group G: 100-400 w/ 1.4x; 200-400 w 1.4x and 2x
Group H: Long zoom lenses with teleconverters
From looking through the list it appears that modern lenses should fall in groups A-D, and that the majority of those should be A or B. That is until we get to the BIF enthusiasts.
So I'm very happy with the performance, but if a person were to buy it hoping for a double cross focus point, look for that asterisk.
It is not completely new that certain AF functions are limited by the lens in use. In fact this has been the case for many camera bodies for many years. It does however seem to be getting more complicated as the generations mount.
The reason I ask about specific first hand instance is, in the past with bodies with similar cut off points, we've rarely if ever run into an actual bottleneck that resulted in complaints of performance loss. Personally I have not. I know my 5D3 and 7D2 (and 1D's for that matter" have similar cut offs, but in use I never really seem to notice a hit.