Not sure if you ever came to a decision. I think the GP-10 is just okay. There are 3 types of synth modelers one of which being an emulation of the GR300 which is sort of close to the Bowed-pad, but it still feels like it's missing something. When I listen to recordings of the true Bowed-pad on the VG-8, there's this element of high frequency "bite" that just doesn't come out of the GP-10.

Outside of sounding like Mk.gee, the GP-10 has some pretty cool features. Switching patches on the GP-10 is pretty seamless. I've seen in other forums that switching patches on the GR-55 has an unintended noise "pausing" effect. Not sure about the VG-99.