Firstly, the value point is not a reflection of the retailer I bought this from. I actually got the best price for this grip, from the eBay outlet.
The grip itself adds around 2.5 cm / 1 inch to the height of the Canon EOS RP camera body. The RP is comfortable to hold, but people with moderately larger hands might find their little finger sitting underneath the camera, or they claw their hand to make the whole of it fit. This grip adds that little bit of extra depth and makes holding the camera truly comfortable.
You do have to remove the RP battery door to fit this - keep it safe as this body does not have storage space for the door. You can still access the battery and card compartment very easily as the grip has an easy access door. The battery may need a bit of help out, but it's not an issue. The card just pops out.
The grip is very well built and looks and feels like part of the camera. It does not add a great weight.
Value-wise, it is very expensive for what it is. Canon knows how to charge for accessories, and they certainly charge you for this one. A nagging thought is that this grip addresses a late discovered design flaw in the body dimensions, and we pay for that.
However, quality comes at a cost, I suppose, and this is far better than some of the cheaper alternatives I've seen advertised.
The grip, shallow though it is is an absolute must for slightly bigger hands and longer lenses. My EF 16-35 f4 L now feels balanced and comfortable. The RP now just feels a complete camera rather than a tiny package. Not exactly cheap but it’s made to a high standard and the finish and fit is excellent.