So one thing I've taken note of is that the client has been amazingly stable, at least on PS3. When FFXI first launched, there were as many client updates being thrown at us during the first few weeks as there were server maintenances. This time, the issues all seem to be at least mostly scalability/performance related, not actual bugs in the code on either the client or server side.
That's pretty impressive.
I've also seen a number of folks asking questions like "why are there all these issues at launch that weren't fixed during the betas?" It seems to me that at least the largest/most insidious actual code bugs must have been worked out during the beta periods, so overall I'd say squenix devs have done a pretty awesome job overall given the fact that I haven't had a single client update pushed, nor had the client go buggy or crash on me.
FFXI crashed all the time for quite a while on PS2 and PC before they stabilized it and that took them months. This is a clear improvement.