Have you actually used the commercial version? It's relatively stable and QAed and you can get support from the Wine developers, but it lags the open source version by months. You're not getting the latest compatibility fixes or performance improvements with it.
nevertheless the commercial version must be of use to someone by addressing pain points that other users don't have. and i wager that it is exactly those small issues that don't bother others but that matter for people willing to pay for it.
