Can I ask why you do not recommend Tauck? We are looking at their South Africa trip because we like the itinerary better than ABD's.
We took a Tauck Bridges river cruise this summer and loved it. If you have done ABDs, there is a bit of let down effect, as the service is not nearly so fawning. The guides were more there as helpers than as complete vacation magic-makers. And the little things like snacks on the bus or surprises in your room do not happen. However, once we got over ourselves and stopped comparing it to ABD, we found that we were enjoying ourselves immensely. It was definitely a better trip for a family with a teen, as there were a lot of kids in that age group, and we were able to book a single cabin for DD18 with no single supplement - not possible on an ABD river cruise, we would have paid way, way more for her to be on a pull out sleeper chair in our cabin.
Haven't done a Tauck land tour, but there were a few families on the cruise who had done both Tauck and ABD and they indicated that the land tours are more similar to Disney level than the river cruise. Certainly the families who had never done an ABD thought the Tauck cruise was the best trip ever. There were some families who were as loyal to Tauck as many of us have been to ABD, with years and years of trips behind them.
If service and attention to detail are higher priorities than cost, ABD wins every time. But if an itinerary or price with Tauck makes them attractive, I wouldn't hesitate to book again.
! So glad you made it out of lurkdome!