This post could be very short and summarized in one sentence: I had Lightroom iPad Mobile trial subscription and I didn't use it even once.
When I got my iPad a couple of years ago, I really wanted to be able to edit pictures on it. In fact, I thought it could substitute my laptop for quick edits and I was really disappointed that Adobe didn't have Lightroom for iPad back then. Well, they finally released Lightroom for iPad a month ago (more or less) but I think it was too late for me at that point.
My main concern was about monitor calibration - there is no way to calibrate your iPad display. I don't want to edit pictures on an iPad and then go back to my desktop to correct the edits because of mis-calibrated iPad's display - it's like doing the same work twice. Of course, I tried Lightroom Mobile during the trial period but I didn't use it to edit pictures in a more 'serious' way. However, I was quite surprised that the picture I played with looked almost the same as on my calibrated desktop monitor.
So why I didn't edit anything on my iPad? I guess I got used to separating 2 different workflows: a desktop and a mobile workflow. The former one is for photos I take with my cameras and I prefer to edit those pictures on my computer. I feel I have much more control over the edits and I spend more time on fine-tuning these edits. The latter (mobile workflow) is for pictures I take with my iPhone and iPad. I also edit these pictures on my mobile devices and upload them to social networks. I don't have a need to have so much control over editing these pictures because they don't have such a great photographic/creative value to me as my camera pictures have.
I guess it's a matter of personal preference.