For me both models are a bit flawed. As hatchbacks, the GTI and R models can get away with comparatively boxy looks in favour of practicality, but as convertibles, practicality is no longer one of the main considerations. The Audi TT loses 2 seats but looks much, much better than either variation and there are plenty of 4 seater options for those wanting something bigger.
The models are taking an awkward ground between cars like the TT and bigger convertibles such as the EOS, A4 convertible and so forth. I don't expect them to sell that well.