There are aesthetic differences between most solar panel brands, as well as differences between efficiency, lifespan, and cost.
What you're shooting for is the best bang for your buck. If cost isn't such a concern, you want to find a brand with the highest standard DC watt rating, and the highest efficiency rating.
When you contact the installers you've chosen, ask them for statistics on the solar panels they offer. The important metrics to ask for will be the cost per watt, DC watt rating, efficiency, and AC kWh output.