I did get the E from Helios - they painted it, possibly fixed some things up. But it wasn't their kit that they built. I believe they have their own kit that addresses all the issues that you see on mine now.
In terms of quality - they are great - I have the C and B on order with them too.
If the D (which they built with their own kit, from the ground up) is any indication - there is a crazy support structure in there and there is no way this thing will sag ever.
I found them easy to work with - if you address your concerns with them, they can surely put a similar support structure in your E to ensure that it doesn't end up misaligned like mine.
I like their electronics, it's slightly a chore to get everything together when they ship it to you. You have to connect some wires and stuff, but it's not overly difficult, but it's definitely not plug and play.
Mind the wait time - these things, like most model makers, take a while.