I am no doctor, so I suggest you speak with yours. I'd wager not many of them are very familiar with e-cigs, however.
Even so, there are plenty of folks here that have been doing this for a couple years and have had no ill effects. I was a medic in a hospital for a few years in the Army, though. I've given my share of breathing treatments, etc.
My answers:
1. It's hardly "copious" amounts of water. A cart has about 1ml of fluid, of that some small percentage is water and of that you exhale a large amount of what you inhaled. Your body will likely absorb the water, if you are healthy.
2. You are correct. You probably should be cleaning your equipment periodically with one of the many methods suggested in this great forum. Alcohol will kill just about anything you are worried about... why not give your atty a soaking once a week? Additionally, there are some studies to suggest PG has it's own anti-microbial properties. I recall reading an article recently. Google it and you should find a few references to studies performed during WWII.
3. It does bother me a little. I tried a couple different companies and settled on the one I use now. *cheers to you
www.madvapes.com*. I suggest you find one or two you trust and use them. After a while I thought about it and figured the same argument could be used with anything else I buy. How do I know what's put in my milk or in my cereal? Sure the FDA is there, but there's plenty of incidents of contamination in recent months.
4. I'm sure you could find a company that you could pay to test samples for you. I can generally feel when I am getting too much or not enough. I guess I can chalk that up to so many years of experience with analogs.
5. There is indeed a growing voice in the medical field. The American Association of Public Health Physicians released this statment some time ago:
http://www.aaphp.org/special/joelstobac/2010/20100402AAPHPEcigLegisStatemnt.pdf. They estimate the nubmer of lives that could be save each year to be 4-8 million if all smokers switched to e-cigs. Pretty strong words. I'm inclined to believe them. Smoking is, without a doubt, bad for you. This isn't news. The things that make it bad are eliminated in the e-cig. Nothing is as good as quitting, but the rates for quitting successfully are awful. So, given we already smoke, what's the harm in switching to a healthier alternative?
It sounds like you need to do some of your own research. I read about them for a good month before I made my first purchase (a Yeti kit). I was a little disappointed with it and got discouraged. I then went out and bought myself another kit (the Joye Ego) and haven't had but 2 cigs in over a week. I find now they taste awful and will not look back.
Good luck to you with whatever you choose. I think the bottom line is what's the harm in trying? It's taking a route your unsure about v. sticking with analogs, which will eventually kill you. It's an easy decision in my bood.