There are plenty of mobile IM clients out there and a few of them work pretty well. I'm sure I'll find one I'm quite happy with, but one of the features of Msg+ I have always loved and will result in my continued use of the addon even if the rest managed to fall to shit is the superior logging client. I love that I can use Msg+ from any computer anywhere and, so long as I am still logged on to Msg+ at home, it will all log on my home computer. (I know plus recently added an online logging feature but it glitched like mad and I had to disable it, sadly.)
One thing I was pretty picky about was finding a mobile IM client that would allow me to be signed on both at home and on my phone to see if that would allow my chats to be logged at home, as with regular MSN, but it doesn't. =\ So yes. I would love the developers to put out a mobile Msg+ for the sole purpose of being able to track everything my friends and I say and do in one nifty place.
That is all.
P.S. I upgraded my comp to Win7 and was forced to download the 2011 version of Windows Live Messenger before the new Msg+ release was out. It was a very dark time for me.
In short, I -love- this addon and don't know as I would keep/enjoy MSN at all without it.