An update:
Just returned from a week-long trip with just the iPad and iPhone along, no laptop. For the most part, I did have wifi available where we were staying, so I typically only had to use the iTether/TetherMe solution for brief periods most days. For those short times--check email, a few forums, the baseball stats--it performed flawlessly each time so long as I had left BT and tethering enabled on the phone, and so long as wifi and BT were off on the iPad when I opened iTether.
I did have one two hour stint of tethering in the Denver Airport on the way home. That session was a little marred by a few dropped connections. Finally I turned wifi and BT off on both devices (even though wifi was not connected on either) and then turned BT back on on the phone before asking iTether to connect again. From that point on, it ran without a hitch--about an hour with no interruptions, mostly light surfing and a couple of downloads (saving webpages and adding a couple of apps). It hasn't again required that I remain on the Network settings page as I noted above; I do just leave the tethering setting switched on now though as there doesn't seem to be a reason to turn it off really.
For $7 total between the two programs, I feel I got my money's worth. Yes, the combo is a little persnickety about how everything needs to be set before I turn iTether on, but it's minor really. As an occasional use solution, it seems to be a good choice.