I've used the Mobile Client Grid for some time. It's great for just text chatting. The bad thing is the reoccurring costs. The standard subscription is 250$L per month. The pro/full version is 400$L per month. The full version allows you to interact with inventory to do things like read note cards, send objects, etc.
The Lumiya app is interesting. I just downloaded it and figured I'd play around with it for awhile.