Hi,
My opnion:

1. VFP has all built-in data manipulation features, optimized, fast (with rushmore technology). Instead C++, you have to use 3rd party product or build all this function yourself. It is time consuming and may not have same performances.

2. VFP is easy to learn and flexible. It will shorten your development time and cost.

3. VFP has UI designer, where C++ no.. (I suppose)

my 2 cents :)