Hi Rob,
Re the tube... I agree that it seems scary, even after watching my son do it for over a year, I would still be nervous to try

. But, really, I am not exaggerating when I say it took him one or two tries with the nurse and he was doing it on his own. He did it slowly the first week or so. At the beginning, he would drink water while inserting the tube (sort of 'swallowing' the tube as he drank) and I would hold the glass and straw while he inserted the tube. But, within a couple of weeks, he was comfortable enough doing it on his own and now doesn't even use the water. It literally takes him 10 seconds to insert the tube.
Here's a link to a girl giving a demo to insert the NG tube. She does a great job at explaining everything, however, she is so detailed that it seems like it's a long process... as I said above, it truly takes my son only seconds.
http://www.youtube.com/watch?v=YJIFOCbPTjo
But, if you don't mind the flavours of the shakes, there is no medical benefit to using the tube over the drinking the shakes... I'm just hoping to make you a bit less scared of the tube so that you have another option.

I think the biggest pros for the tube is that you can skip the 'taste' of the shakes if you don't like them and you don't have to worry about making sure you get the necessary amount every day; however, the con is that, since you get all your nutrition overnight, there is some hunger during the day (especially into the evening). My son was allowed clear broth, pop, freezies, jello, etc. to help fight the hunger but it only helped a bit.
As for the diarrhea, my son had diarrhea for the six weeks he was on exclusive EN. There were no other symptoms nor any urgency. This doesn't happen to everyone but our dietitien did say that some people react this way as 'what's going in is liquid, so what comes out will be liquid'. This went away as soon as he added food back in to his diet.
If you have any other question, please ask!!! Good luck!!!