I have only had my Mele for about 3 months. When I bought mine at the store they didn't have the one I wanted but had it at thier local factory (as stated earlier, the finishing and setup occurs on Maui). One thing the wife and I noticed is that most of thier stuff came with either a Matt or Semi-Gloss finish and we wanted a gloss finish. Eva called down and found one they were just finishing up and they were able to put that coat of gloss on it for us. I was able to pick it up the next day.
I spoke to them at length about how they stand behind thier instrument and they basicallly said that they will stand behind any defect in material or workmanship, the only thing they will not cover is if the instrument was not taken care of properly. In particular, I live in Minnesota and our winters are brutal on instruments like these because it not only gets cold but very dry. Tropical woods need hunmidity and if they are deprived they can shrink and crack. I know this first hand because I have a Tangi Mango Tenor that this happened to (FWIW, Tangi took care of this for me...). So if it's dry where you live, invest in a good humidifier atleast for the case so you can store your instrument in a suitable environment, and don't forget to keep the humidifer wet...
Another thing to remember is that you will likely see Mele's at some of the other stores you visit. I know Mike at Kula Gold has a couple and I seem to recall that Lahaina Music had a few too. The other two stores I mentioned didn't have them though.
If you don't think you can maintain a proper environment for your new Ukulele, you might want to consider a Koa Laminate, they tend to tolarate the drier weather better.
The best advice I can make is look for what you like and listen to it. See if you can hear the difference. I know I do, or think I do. The solid wood ones seem to have a richer sound to them, at least to me.
BTW if you go to Kula Gold, tell him John said 'hi', I bought my Tangi Mango Tenor there.