If you are mainly interested in health issues i guess you will not be able to overlook the volcano.
To my knowledge only a few vaporizers have been tested from a medical perspective. The Volcano is fully medically approved. Of course that comes at a price tag. With the volcano its impossible to burn your herb, with most other vaporizers its quite easy. If you want to make sure that you are as "clean" as possible i do not see many other options.
I started vaping out of similar reasons. All my friends already knew i was coming because they heard me coughing in the stairway. So i started to do some research on this topic. There is no other device that was tested as the volcano was. Due to its forced air nature it can guarantee a pretty stable temperature.
Here are some links for your reference:
http://www.ncbi.nlm.nih.gov/pubmed/16637053
http://www.canorml.org/healthfacts/...-Drastically-Reduce-Toxins-in-Marijuana-Smoke
http://www.vapormed.com/volcano-medic-vaporizer/en/study-research.php
The solo is a very nice vape indeed. I really enjoy it, but its also pretty easy to burn your bowl there if you "fade" away during usage. Same goes for my other vapes. A MFLB will for sure "toast" your bud if to not pay close attention. With the LSV it is the same thing. If you fail to use it properly you will burn your herb.
Now that i am two years into vaping i see things a little different. I am not so concerned anymore, mainly because all my respiratory problems dissipated completely. So i happily use all my vapes without worrying too much. Two years ago i was in your spot, wanting to quit smoking all together and looking for a healthy alternative. So i dived into e-cigs and vaporizers. I forgot about the e-cigs after 3 month, but the vaporizer is still my darling.
Now back to your original question. You will for sure end up with multiple vapes. Mainly because there is no single all purpose wonder machine out there. There are currently so many nice vapes out there so its very hard to pick one nowdays.
Try to analyse your usage-pattern and life style to find the device that suits you best.
Think about the following questions:
Do you need to hide your vaping, and vaping equipment?
Do you need portability?
Do you want to pay full attention to vaping or do you want to vape while doing something else (like gaming)
Do you mind handling glass pieces?
Based on the answers you can try to narrow down your choices.
For me its like this.
I have a volcano sitting on my pc i use while gaming. its perfect for that because once the balloon is full you need to pay zero attention, no chance to burn anything.
But its a very bad device if you want to watch movies. The unit is rather loud on filling the balloons and the balloons itself are like a bag of chips. So there i use my solo. I really enjoy it, no power cord you can just sit and relax without any noise.
When i party with friends we use the LSV + water pipe adapter to have some fun. Its more work + cleaning but its worth it.
Finally when i am outside and stealth is an issue my MFLB comes into play. Each one of my vapes serves a purpose and i would not want to give one away. It would be also hard to pick one as the single "best" one since they are so different. It all comes down to what you want to do with it.