Hello canadiense.
>> My biggest concern is as with all 3rd party tools, when Microsoft sends out a new SP, is there a chance that might 'break' some of my forms?
While it's impossible to categorically state that this will not happen, the likelihood of this happening is almost none, and I haven't heard of such a thing happening so far. We also have a vested interest in making sure that qRules works with all the latest versions of InfoPath and SharePoint, and when InfoPath and SharePoint 2010 were released, we updated qRules to provide special support for that.
>> And can I simply use it to perform certain tasks and then uninstall it afterward? Or will that cause all the qRules commands I use to stop working?
qRules must remain injected in your InfoPath forms in order for it to work. It acts as the code behind the form to provide functionality that can only be achieved through code. You can, however, uninstall qRules from your system once you have injected it into your forms, if you care to do so for some reason. As long as it's inside your forms, it will continue to work.
>> Finally, is there a command you get that makes copying one repeating table to another easy?
The CopyTable command is a very straightforward way to do this, but it requires the source and destination table have the same number of fields, and in the same order. We tend to favor an approach that's a little bit more involved, but more versatile, that I demonstrate here:
http://www.infopathdev.com/forums/p/20492/71100.aspx#71100
Thank you for your interest in qRules!