alllikeme.in is Yii.1 
powered website helping local businesses to create free website.
Yii framework has beautiful structure to adopt 3rd party API’s with great performance, in website we have 90 database models and very large structure.
With fine tuning Yii is great to handle very large websites.
To handle millions of records we are using AWS RDS, dynamo db databases, for cache high request pages we use AWS cache and to serve static css,js we use S3 with AWS front.
To handle large uploading by users we integrated Google’s Cloud API with YII.
Yii is beautifully designed by professionals and it can be integrated with any 3rd party API’s, here for Alllikeme.in we are using AWS and google Cloud service.
Yii2 is in market, but it is difficult to migrate full website from Yii.1 to Yii2
Any new startup I will recommended Yii framework for PHP based application.
It is very professional and clean framework to keep control over large scale websites.