agree with the above from 6
id be wary of anyone that would fit the kit of your choice if it isnt their prefered equipment. Panels are similar but for instance i wouldnt touch some as the engineers are not trained on it or have experience so support will become an issue at some point. Also look for how long they have been going, you dont want to go with someone that wont be available next week. This is usually the case with the cheaper firms as they cant afford to survive and end up moving to something else