Well, my impressions of Arx so far...
For starters I need to give Apostate, whoever he/she is, kudos; I came in knowing nothing about the theme and I was just Guest4, but they helped the hell out of me. Usually I barely get pointed to the correct help file by staff in most games let alone anything useful I can use to build a better character but they actually collaborated with me, took my ideas and added to them, made sure to offer options and alternatives to their suggestions, and... well, it was top-notch. That stuff makes for an excellent first impression.
The lack of meetme is a bitch but at least @directions works...it's a little tiresome after a while - I hate navigating in grids in general - but I could get to events every time so that's good, right? Speaking of, their +event system seems less feature-rich than in the nWoD MU* I've been playing, as unless I'm mistaken there's no way of telling who/how many people are currently going or become able to run a first-come first-served scene.
Speaking of such scenes... not sure if there's anything like temporary rooms either. I want to run PrPs (one of the great things about fantasy settings is the freedom you get) so I'm not sure what the procedure for running one is yet, but I guess I could always hijack a grid room for that - assuming of course that's permitted. Is it? I've no idea. If staff wants more things ran they need to make clear what the rules are though.
Finally the code seems intriguing, I like the idea of a coded combat system a lot. I don't even mind the fact equipment is coded so they're trying to shift what you're wearing from the @desc to the actual coded items, as that offers roleplaying opportunities for crafters and tailor/seamstress PCs. They do need a primer though for things like 'how do I get gear', 'how do I fight a guy' and of course 'I'm a Storyteller, how do I run NPCs?'.