I've had great luck with 10gtek modules both with Mikrotik gear, with DACs, and one that is connected to an upstream juniper switch. I'm curious what modules were the most troublesom.
* I will note that the 10gb sfp+ modules from 10gtek on a Mikrotik just don't work.
Funnily enough, this 10gtek worked on one of my 3 switches, but I could only establish a gigabit connection. I returned it [1]
These 10gtek fiber modules on the other hand have worked flawlessly so far. [2]
This Mikrotik module would not establish a 10 gb link with my Thunderbolt dock no matter what I tried. Works fine with my servers though so I swapped it out.
I've pretty much resigned myself to just buying the full brand Ubiqitui SFP+ adapters [4] for converting to copper.
I recently purchased [5] to run to my living room, but I have not found the time/energy to do the run.
I tried converting everything to copper as well but the copper DACs use a lot of power and ended up not working out due to the greatly increased power usage (mostly because the networking "closet" wasn't really designed for it). So beware if you're moving it to copper
Make sure you also pay attention to the distance rating of the SFP. I had a very similar experience with modules not working at the right speed sometimes. Turned out I was running 50 meters of cable over a 30 meter SFP. Got the correct one, and as low wattage rating as possible and it's been rock solid ever since.
btw, if you are using 10gbe copper modules, take a look at their temperature. some of mine were getting to 92C i think. had to put a bunch of heatsinks on them
I put a couple of Noctua NF-14 over the top ventilation holes in my rack, with the silicone mounting thingies and the NA-FC1 PWM controller. They are almost silent in winter. The switch with 10Gb copper is under the fans.
i opened switch and put noctua inside to cool sfp cage that i added heatsink to, in addition to heatsinks on sfp+ module itself. it dropped temperature from 92c to 75c. year later i replaced it with fiber run.
I have found that a fiber patch cable paired with two SFPs is cheaper and more power efficient than an equivalent UTP setup. This lead me to move to all fiber/DAC for 10Gb save for the 10Gb UTP link to my router that lacks SFP.
I have the 8 port 10Gb + 1 Gb from mikrotik and the UTP SFP's run stupid hot because they have to drive a cable at GHz speeds. The fiber and DAC (direct attach cable) SFPs are cool to the touch by comparison.
* I will note that the 10gb sfp+ modules from 10gtek on a Mikrotik just don't work.