The following are important:

Equipment brand and models being used
Do they use flex?
Number of returns
Pipe size used.
Rebar sizing and spacing
Floor, wall and bond beam thickness
Strength of the gunite
Flagstone type. Oklahoma Flag tends to be soft and not last due to erosion. While pretty, it shouldn't be used, IMHO.
What if they hit rock? Added costs for the dig?
How big is the sun shelf?
Warranty periods?
Visits to pools they have built and are building are important. Asking these people what when right and wrong is important due diligence on your part.
What is the pay schedule they want?

Scott

Thank you for the additional questions Scott-
these are his answers
The equipment brand we use is Pentair.
We do not use flex - Schedual 40 PVC.
3in Dual Main Drain with 10in pots.
There are 4 returns, returns are 2in.
Rebar is 3/8in on the walls and floor with 10in centers and 1/2 4 bar and beam.
Bond beam is 12in, floor and walls are 8ins.
Strength of the gunite is a 6 sack mix.
We use flagstone on all of our jobs, although if you would like brick it would be $800 more.
The sunshelf is 6ft or custom at no extra charge.
Pentair has a 3 yr warrenty.
Polaris has a 1 yr warrenty.

If you have Pentair, then use a Legend and get the 3 year warranty. He just wants the vacation for selling enough Polarises.

Scott

Scott correct me if I'm wrong, but I think getting an Intellibrite LED light counts toward the 3 pieces of equipment needed for the extended warranty. Then they could go with the Polaris cleaner.

Of course nothing wrong with the Legend either.

Okay, I looked it up. What I found said you had to buy a pump, filter and one other item. Lights , cleaners, and other assorted things qualified.