I've only been using Tresiba (Degludec) for about three weeks. In my opinion, that's not long enough to accurately gauge its effectiveness, but I'll share my experiences so far:
-It seems to have no issues lasting a full 24 hours. I give myself an injection around 8pm every night and the basal tests I've done have shown it's level 20-24 hrs later.
-I've noticed occasional rises around 4-6am. They're very slight (less than 2 mmol/l) usually. I've dealt with similar issues (but much more pronounced) in the past, but was able to correct it entirely when I began splitting my (Levemir) basal into a larger injection around 8pm and a smaller injection at 4am.
-All in all, it seems to be working as good as my Levemir. That's an extremely good thing considering that my last two a1c results were 5.4%. The only downside is that I feel that I've lost a bit of flexibility with Tresiba since it's more intended to be injected once a day (admittedly, I haven't tried splitting it up yet).