Personally, I like to get a lower price for a longer vacation. So you will find me chartering from the second tier charter companies.
I've used Conch for the last 6 years and I've been pleased every time. The boats are not new and I've had a few things break down. I just consider it par for the course...I get breakdowns on my boat at home.
In trade, I can afford to go more often or to stay longer. This is what works for me. If price is no object for you, then you can go with the guys with the new boats.
I have provisioned through Conch and without. After trying both, I perfer to provision through Conch, who deal with Bobby's Market, but to provision a little short. I find I eat less than I think in the tropics. I use their on-line check list for the advance order and it is on the boat when I check in. Inventory before you go. Then I can top off at, maybe, Spanish Town, with whatever is popualr with the crew. I have a minimum of leftovers this way and on a two week trip, eventually someone wants to go to town, anyway.
Enjoy yur trip,