Is T6s Good for BIF?

KwhyChang wrote:

I'm thinking it's the same sensor in the 80D and T6s

Actually completely different sensors and technologies.  The 80D has the new 24 MP Dual Pixel sensor (with improved dynamic range).  The T6i/T6s also have a 24 MP sensor (though non dual pixel), which will give you markedly increased cropping capability over a 20D.  Noise characteristics and overall IQ have been much improved over the years also.

and it looks like the T6s is using the old focus system of the 7D so it's no slouch.

Exactly.  Canon upgraded their AF algorithms a while back, and it really shows in the keeper percentages up and down the product line (incl with the original 7D's v.2 firmware update).

Never had any lenses micro adjusted but am fairly sure a 24-70/2.8 that I sold probably needed it. Is that an expensive and time consuming thing? I do have a few of Canon lenses.

I've had a number of lenses that either front focused or back focused.  It's most apparent with large-aperture primes (or telephoto lenses).  Micro Focus Adjustment lets you compensate for this (without needing to send your body and lens(es) to Canon for calibration).  Some folks have gotten lucky and not needed MFA, others not so much so.  YMMV

As far as body choice goes between 80D and T6s if you have the bucks, go with the 80D (or even the aforementioned 7D2).  If your requirements do not extend too far into the fast action category, then the T6s will have you covered.

But I gotta tell you, I really love that dual pixel AF coupled with the marvelous touchscreen.  Just great for macros, candids, and videos (if that's your thing).

Hope this helps!

R2