I'd say it depends on the cost and the urgency...
Most exams should run about $40, depending of course on the vet. I had a place quote me $65/dragon but they had no experienced vet there so I'm waiting for a trustworthy lady to come back from New Zealand in about a week or so to schedule with her.
Just make sure you don't get taken advantage of - kind of like car repair shops. Exotics vets, experienced ones anyway, are hard to come by in some places, so people could jack up their price for no good reason.
If reviews are available for both, I'd comb through those and see what people are saying.
The cold will slow down the worms so they are less productive with moving to their pupae state. Too cold will kill, and it will also slow down their eating so if you are gut-loading them it can mess with that. Other than that, I just keep them in the container the arrived in. Why not?
I order BSFL 500 large at a time to make sure I can go through them before getting too many casualties. Most of these go to my youngest, then the older one gets the dark ones etc to go with his salads and occasional roaches.
If you're interested in trying roaches, as I mentioned I buy mine online. I'm not trying to promote any specific seller but I feel the best supply comes from ABDragons. Very good quality. I've tried from other sellers but sizes are super inconsistent and packaging can get.. weird.... I have 500 small roaches coming for $24 if you needed a price-point.