Anything in particular I should look for?
Definitely stay away from the 'answer in a can' product at home depot. That is around $40 and it's rental property grade product. You cannot expect much from that design.
The 'majority' of applications I've seen using this product have been for more established property owners, in which only 1 or 2 people are using the tub on a daily basis.
Every once in awhile I see it done on a house where multiple people live, meaning upwards of 4-5 people with kids.
There are numerous companies probably in your area that do this type of work. I would recommend anyone that has over 10 years in the business in one location, a clean BBB record that would lead one to believe that the reliability of the product is holding out.
One crucial mistake made in this application:
Those who put these new finishes on MUST remove the chrome trim for the overflow opening along with the tub drain chrome opening.
That is 2 areas where porcelain always comes off/rust shows up and can create a bad situation down the road when the trim is replaced and that area is slowly going beyond what the trim covers.
If the first statement that comes out of their mouth is "we are not plumbers" then tell them they cannot do their job correctly with leaving those two items intact. That's not how the tub was first glazed and they know it.
They should have a plumber that's available to do the task so your investment lasts.