First, my apologies for missing this thread for so long. I usually try to reply as soon as I can.
It's good that you're doing your research -- the software deployment model is critical for an MMO; your users absolutely must get the latest version of the client software as soon as possible, and if it's a subscription-based MMO the user experience during updates can be of critical importance as well.
Note that the list of companies on our web site isn't complete by any means; I think our web department literally just chose the logos they thought looked the coolest.
Unfortunately we don't have any more specific information we can divulge about our customers.
I know that we have customers who use our tools internally, even though they are forced to use the publisher's tools for public releases.
(In the game industry in particular, deployment tools are often either chosen or mandated by the publisher, for various reasons. There aren't that many publishers out there, so we don't see a huge variety in deployment tools.)
However, if you have any specific questions about the quality or reliability of our products, we'd be happy to answer them.
TrueUpdate in particular is extremely robust. It uses industry-standard protocols, is completely server agnostic (so you can host it on whatever hardware you want, take advantage of load balancing, uptime guarantees, etc.), and has built-in support for server redundancy -- in fact the download logic is entirely scriptable, so you can design it to choose from multiple mirrors based on geographic location, etc.
TrueUpdate is also unique in avoiding privacy issues because it is entirely client-initiated -- no customer information needs to be sent to the server in order for the update to occur (unless of course you want to send information, for example to gather statistics or perform access validation).
The other tools don't care whether you have 5,000,000 users or just 1 -- once an installer or patch is downloaded, they run locally, just like any other executable on the system. (Although they both have some scriptable HTTP communication abilities if you want your installer or patch to "phone home" for whatever reason.)
Setup Factory has been in use for over a decade. It performs archive integrity checks prior to installation, does failsafe copies, and can automatically backup any overwritten files.
Visual Patch performs MD5 integrity validation on each file, and it has full rollback support, so if anything happens while applying a patch it can completely undo any changes it has made. Visual Patch offers a full library of scriptable actions, so you can perform any additional system changes (Registry, INI, XML, etc.) or integrity checks that you require.
It also benefits from having the fastest patching algorithm of any tool we've tested -- in fact the patch engine is so fast that Visual Patch can perform multiple passes in order to discover the best settings for each file, and still do so in far less time than most other tools take to perform a single pass.
Incidentally, most of the team here at Indigo Rose are avid gamers. I've even played a few MMOs (WOW, Guild Wars, Planetside, EVE Online). So if you have any issues at all during development they certainly won't fall on deaf ears.
--[[ Indigo Rose Software Developer ]]