Quoted from Boat:

Congrats. Test every single switch and coil with them. (There are diagnostics/tests they can run off the machine)Make sure they fix any issues you find. If they say don’t worry it’s an easy fix, then get them to do it for you.
I’d also recommend playing a bunch of games on it to see if anything else is out of whack but it almost needs to be levelled before you can do that not sure if they would entertain that.

Quoted from LTG:

Look over hard to clean areas. Are they clean or dirty. Look at the boards in the head, do they look new, or serviced with the right tools or parts, or do the boards look hacked or battery damage on cpu ?
If you can, bring a friend that knows pinball with for another opinion.
Don't get caught up in having to drag that first game home no matter what. Make your first pinball machine a great experience. You'll be glad you did.
LTG : )

Quoted from EvanDickson:

Make sure the pf moves smoothly up and down through all 3 positions.
Make sure the upper flipper can cleanly shoot the ramp.
Make sure all 5 dalek armor targets / optos are working.
Make sure the display is crisp and clear, no missing lines or columns, no degassing in progress.
Make sure the boards have no weird hacks.
Make sure there is no corrosion damage to the mpu. Even slight corrosion can make the mpu break down.
Make sure battery holder is removed from mpu and either placed remotely, or replaced with nvram.
Do a switch test to make sure all switches activate correctly, and a solenoid test too.
Play some games and hit both flippers at the same time a bunch to test for the Williams reset issue, if the game has it then the power board will need new caps, rectifiers, and lm323. If the game has a little daughter board between the power board and you, then it probably has the issue but it's being corrected by the daughter board. In that case it will need a power board restore soon.
Warning. Keep hands away from mini play field.
Congrats, awesome game, a long term keeper!