There have been a few instances only where there have been minor hiccups, (but am not sure if the problem has been at my end with my ISP) so generally and overall, can't say that I have issues with them.
I'm using Odin with a regular broker. I have the zerodha account but had major problems with Nest so left.
Pure conjecture, this, Nest needs a very good net connection on your side and theirs.
Now I'm looking for a discount broker who provides Odin.