Hey Summit151, Shoot me a pm, The family has a townhouse in Mazatlan and I've been out fishing a bunch of times.
Go with Chappy Chapman. He is the owner of Inside Outside Charters and is a fishing fanatic!, I've got a review posted on trip advisor on one of my trips out, just search insideoutside.
Depending on what type of fishing your into he will hook you up, hes got the best tackle in town and decent boats. I prefer inshore fishing - cause there is way more action. Some roosters might be in town ( large ones don't show up until summer months) there should be some schools of jack crevelle around which is tonnes of fun gunnin around pitching top water raps to them.
If your thing is the offshore deal then he can still make it happen, I haven't done that with him yet, as most times I'm there I'm chasing inshore fun. For Marlin I go to Cabo - not as far to travel out to the bluewater as compared to MAZ. You can still take a marlin in Maz but its mostly stripers, and only certain times of the year - I know 2 were boated last week in Maz the same day, (for Maz thats a good day).
and of course there is always the chance of sails, and Dorado too.
Anyways - Any questions shoot me a PM. - if your interested in setting something up with him let me know I'll fwd your name and he should give you atleast 15% off. (again usually not hard to do in Mexico). and if your looking for someone cheaper ( out of the old marina - older boats, etc,etc. I can give you that info too.
if nothing else, have a good trip, and I expect a fishing report!
Cheers.