Cape town is very small, just the small bar and like 3 tables which often get filled up by families waiting for tables at Jiko. It is also pretty secluded, so you don’t really have a view of anything but the check in counter for Jiko. The only reason I would choose it over VF is if you want to eat some of the dishes from Jiko, since you are eating at Boma I doubt that applies. VF is larger with more seating and a better view/atmosphere.
ETA: I have never paid attention to the wine list at VF, so that may be the only negative if they have a smaller wine list than Cape Town, but I haven’t compared the two, so they may be the same since the two are so close.