John
Generally I think that uTasker makes Ethernet projects much easier and efficient since it allows immediate Ethernet/networking operation (since the Ethernet driver is integrated and can be easily used for networking with its integrated TCP/IP stack or for RAW frames, or for bridging between multiple interfaces (like Ethernet RNDIS over USB or WifI or G4 models and such)).
Allowing EtherCAT master firmware to run on a PC on a simulated i.MX RT part makes for simpler development, testing and debugging too (also when HW is not yet ready, which can give a project a big leap forward).
However I am wondering whether you already have HW that is capable of dual Ethernet since there are no NXP evaluation boards that support more than one (unless you wait for the i.MX RT 1170 EVK which should be released fairly shortly).
The uTasker dual-Ethernet driver/stack has been developed on custom HW and so will need to be proven on more when these become available - which will presumably be the same case for other driver sources since they probably don't support dual Ethernet use since it is not presently "standard".
Regards
Mark
P.S. Note that the uTasker project doesn't just give Ethernet and networking but also USB stack, file systems, graphical libraries and many industrial control solutions fully integrated into the same project/package. It also includes FreeRTOS mode. So Ethernet development should be much faster but then most other aspects of the overall product development will tend to be much quicker too so generally there are numerous advantages, all boiling down to quicker and cheaper project developments and shorter time to market.