Well, I can say this much as for having experience with both Alliance and 2 other distributors...
When I contacted Alliance in 2012 just before opening Aries Games & Miniatures...so I could setup my account with them, they literally treated me like crap. Not polite, basically said because I was starting out I wasn't good enough for an account with them, etc. etc. etc. I thought maybe I got a bad contact, so I called back on a different day and got someone else...and the SAME treatment. I was pretty disappointed as I was told over and over "they are the ones to go with".
So because of it, I reached out to ACD Distribution, and was treated 180 degrees different. Very welcoming, respected the fact I was starting out, etc. Their selection of Catalyst products was horrible and got worse as time went on...
So I made an account with Golden Distribution and have been almost 100% satisfied. Phil has been awesome to work with, always tries to get back to me ASAP, and while he didn't have ALL the correct info which caused a panic when I announced the same info on the landing of the box sets...I stick with him. I'd LOVE a better source of Catalyst products...but I buy several other lines from them.
IWM has nothing to fear from being left out of Alliance. While they are "big" perhaps they are "too big", kind of like when a company grows too much and loses the "customer service" aspect of their business and concentrates only on profit. I'd say what I really think of Alliance...but I'd get booted from here.
Golden is a good spot for IWM, not just because I buy from them, but the group there goes out of their way to get their customers taken care of, and Phil knows Loren...so when issues come up...they get resolved.