I've just moved from a Mk2 to a Mk3 on my ADSL service and the SNRM is higher and appears to fluctuate less too. After a resync, sync rate is a little higher too. I'll monitor to see if the improvements are sustained...
Off topic but, I have an unlocked Eircom F1000 that I've just configured to run as a modem only so will install that at some stage to look for further improvement.
This is all in preparation for migrating to fibre (everything crossed) in December.
Service: Talk & Surf 100
Modem/ router: Billion BiPac 7800N
Target SNRM: 3.3dB or 52% of ISP
Current sync: 9755kbps
FTTC cab in place but not enabled..... yet!