I don't trust any builders. Ultimately they work for themselves. You need your architect or PM to hold them to account.
I've seen first hand the problems when the architect and builder get too cozy, essentially, it's a gamekeeper and poacher scenario.
Hire the architect and design team, then a QS to build a BOQ, and run a competitive tender to 3/4 good builders to find your builder.
You don't have to go with the cheapest, but you need to run the process. Unless you are skipping the main contractor altogether and running it yourself (as many on here do).