For those interested, here's a comparison of the tracks from my new 735XT (blue) with a fenix 3 HR (pink), both set for 1 second recording. First time using mygpsfiles.com, so if something seems off let me know and I'll upload again. FWIW, I paused the run a few times (for reasons unrelated to the comparison) and the 735XT measured longer than the fenix by about 0.07 miles. I had both watches set to record a 6 mile run, with 1/4 mile warmup and a 1/4 cool down.
Have posted the comparison in the fenix 3HR forum also.
http://www.mygpsfiles.com/app/#fh73x00B