Dongle-E performance using this FW vs the stock?

[Ltek]

Anyone switch from a recent stock FW to this and find any performance benefits? With the stock (on latest version too) I get a lot of disconnects with end-node devices and router devices that dont even connect to the nodes closest to it. But oddly, the routers connect fine to each other even when 2 floors away.

[Nerivec]

By "stock firmware", I assume you mean the ones from the itead repo.
If so, they are not quite as tailored for Z2M/ZHA use as the ones you will find from community builders. We've taken extra steps to improve stability and various capabilities.
That said, every network is different, so, your question about performance is pretty hard to answer. If you use groups a lot, I'd recommend switching. Same if you have an unusual network (size/shape).
Though, in general, switching to a community build is usually a good choice, if only because we know what parameters are used to build the firmware (open source builder/manifests).

As for your disconnect troubles, they are likely unrelated to the firmware. Some brands are known to cause troubles with joining/adapting (Tuya, Aqara...).
Note: (good) routers are always more capable than end devices due to less power-constraints.