I have concerns about the "netcode" but I'm not sure how inherent to the engine or not it is - there are a few things that can be delayed and/or inconsistent which are due to it - but the last round of the beta is the only one I've seen it truly as bad, aside from the railgun, so it might be just they are tweaking it dunno.
I've got a bad feeling it is going to go the way of so many betas I've been on before i.e. ETQW - they get about 75% of the way through development and the "netcode" is in a good state just needs some minor tweaking mostly to reduce bandwidth and tighten up a few aspect but they go overboard trying to make it use as little bandwidth as possible and just mess everything up and ends up on release with very meh "netcode". For instance with ETQW up until about 3 months before release the "netcode" was pretty much perfect once they'd sorted some vehicle prediction issues - occasionally you'd get some undesirable hits after you'd gone into cover but IMO it was worth it as a trade off as it was bang on in every other respect bar that it used about 12kbyte/s upstream which was considered too high at the time - though I'm sure some compromise could have been made for dialup users without destroying it for everyone else. Then they went overboard tweaking the area of relevance system and everything else to a point where the game had impressively low upstream bandwidth utilisation - but never felt half as good to play.
I'm hoping they work on the mouse/put in more options as well as with more extensive playing I've realised I'm getting negative acceleration at times which is ******* my aim quite a bit in LG fights, etc.