If your starting with 10 lines and 18 phones, what will be your projected growth over 7 to 10 years? You should do your projections then look at systems that will meet or beat that capacity.

I like and have sold a lot of DX80 systems and I like them and I don't think they look or act "cheap" but that's just my opinion.
Most of these systems are pretty equal in abilities and endurance, Id rely more on the projections for size.
Mark