Sheng Siong supermarket has limited range of meat (esp Beef). Their strength is pork. The F&B options there are limited and meh but if it is sufficient in your opinion then good for you. It's not for me.
I haven't tried any of the shops in Clementi Peaks since they opened.
Clementi Ave 6 has a supermarket in the new flats behind 201-206, towards PIE / Clementi Camps direction and some F&B options. Like you said, it is limited. Within Faber estate even worse. But that could be said of the landed in Bukit Timah as well, Watten Estate also. Only got 1 small area for eating near RGPS. Other than that, not that livable if you want proximity to amenities.