Do you have any existing irrigation to begin with? A controller somewhere, some valves controlled by a controller... What kind of irrigation are you looking to get? Are they just going to convert existing risers to drip or something like that or everything is new?
Irrigation can be a little complex if from scratch as you have to calculate pressure & friction beginning at the source, the well or main, all the way to the last emitter to ensure you have the PSI needed for the last emitter. You can easily loose 1.5 psi per 100' at 4 gallons per minute. Corners, Values, Back Flow devices also all cause a reduction in PSI due to friction also. Also, an elevation drop can increase your psi, but elevation rise will diminish it.
If it's more that just a single line they should also be talking about hydro zones. A hydro-zone is the area serviced by a single value. It should be understood that the hydro-zone serviced should use complimentary valves or emitters and service plants with similar water needs.
There should always be back-flow devices in place for every valve also, this ensures any contaminants in the irrigation are not allowed to flow back into the household water system. In most residential systems it is built into the valves, but overall the back flow devices should be 18" above the highest head.
One other thing is if they are installing a controller see about moisture sensing system that will not irrigate during wet weather.
These are some (certainly not all) considerations and concepts that should be part of the conversation.
In looking at their web age the gallery looks like mostly hardscape. I you have time you should talk to more than 1 contractor and they should be able to give you estimates for free. If it is a bigger project they might suggest or require a design and usually there is a fee with that.
Irrigation principles are very different from most other gardening tasks, they are unique and fun in many ways.
