So, I decided to stay here in the end and I would say the stay was okay.
it didn't start well:
2 weeks before the stay I called IHG to use my suite upgrade voucher and was confirmed a Sanlitun view junior suite - 70sqm. On the day of arrival though, the hotel blamed IHG for confirming a room type that was too high and downgraded me to the lowest junior suite, 50sqm. After a 3rd email to IHG and the night manager calling at 2am in the middle of the night to ask about my complaint, they finally moved us to the room that was confirmed.
The breakfast was okay, quite limited for a hotel in Asia. However what stood out was the club lounge, the food quality there was excellent!
As a first time visitor to Beijing the location was a little too far from the centre, but taxis are very cheap, around 4 USD to forbidden city - and Didi works well for foreigners through Alipay. Next time I'd try the Regent.