Don't need Bluetooth but my BX510 (also a 'lightweight' model) had failed. Hope the heavy version holds up better.
FWIW, my X800 (purchased July 2017) was always flaky and appears to have died on me. Had frequent freeze-ups requiring unplugging the power cord which was a PITA when the power strip was easily accessible, but is a MAJOR PITA now that I have the strip buried behind my TV stand. It was stored for over a year while I house-hunted and then moved, but had been perfectly behaved at my new house since April until a couple nights ago when it wouldn't turn on and unplugging (even leaving unplugged for over 12 hours) had no effect. Extremely disappointing.
Pulled the trigger on an X700 because it's $75 cheaper than the X800M2 and obviously being built like a tank didn't prevent my X800 from defecating the sleeping place.