Most user friendly review sites for Google Shopping

[NetvantageMarketing]

Hello all,

Have multiple ecommerce projects going right now and thought I'd throw this one out there. We use follow up emails to try to encourage reviews for customers to all of our ecommerce stores, but find that many of them are pretty tedious as far as registering to write reviews and requiring a lot of information to get started. We primarily use Reseller Ratings and Trustpilot, but were interested if anyone had better luck using some different sites that Google also crawls for review data.

Any input is appreciated.

Thanks.