For performance, all Silicon panels are basically the same. There is poly and mono, mono being about 1% better than poly for a given size.
Other than that, its just price, so shop for the best deal shipped to your door
The CEC lists STC/PTC values, there is no point in testing since its all the same technology, silicon that is. Inverters have different typologys, firmware ect that can only be compared thru testing, thats why ther is the need for the tests
http://www.ecobusinesslinks.com/solar_panels.htm for your shopping based on price