Okay I have messed around with Arrowchat ALL day.
I find that it's pretty good. Not perfect, but pretty good.
The one thing my members hated was the mobile option. It throws everyone into a "whos online" list and there is no way for users to opt out.
They don't like being added automatically to a chat room. Also there is a little mobile tab that pops up letting them know chat is available. There is no way to remove the tab on a per user basis until further notice. It has to be shut off with each visit to the site. Because the mobile features are not customize-able enough for my users I had to disable it.
Desktop chat is pretty awesome..
Mobile chat is lacking. Mobile needs:
way to opt out of showing up in the online list. (desktop has "be unavailable for chat", mobile has no equal option)
way to remove the mobile tab floating link until further notice on a per user basis.
FYI I am integrated with Invision Power Board 4.1