Courtyard Sha Tin has a lounge and good elite treatment. The Ovolo is a design hotel - so you'll get a bit of a welcome drink but its a very different set-up as whilst they'll do good elite treatment they don't do a lounge. Rooms in Sha Tin should be bigger and have a nicer view as well (river view vs looking over a football court at the best in each hotel). The breakfast at the Courtyard is also a more extensive buffet option vs an al-la-carte at the Ovolo (from memory).

It's hard to ignore the location deltas to be honest - there is quite a bit around Ovolo and its easy to get into Central, Wan Chai or Aberdeen -> ShaTin obviously has its own nearby town.

So in summary you could definitely stuff yourself with food and drink more easily at the Courtyard via the lounge and breakfast, hence being better value, than the Ovolo.