I've worked for both companies. I would not choose either. I also use to be a photographer at Proex I highly recommend them. Or highering a private photographer but that's more exspensive.
Here are my reason's why to choose Proex:
They have appointments that they keep to,they don't run behind (maybe occasionally at xmas time but generally they don't)
They give you exactly what you want not packages where your overloaded or talked into buying that you don't need.
Photographers don't get commission on sales your not talked into anything.
They are price competative with everyone else
They photograph pets
They are more personable and are willing to really work with you.
The training at Proex is AWESOME I had the crappiest training at Penny's and Sear's but when I was at Proex WOW I had very very exstensive training offsite and had follow up training every year.
I am no longer employed by any photography studio's so this is not a biased opinion. I left Proex a few years ago and still bring my daughter there or I take the pictures myself.