I don't own any Festool kit so don't have any axe to grind or boasting to do!. I am following this thread with interest as I am possibly going to buy a domino one day. I did go onto the FOG when this thread was started and had a look about. I looked at one thread where several people have had problems with their Kapex saws and Festool, although aware of the long term problem, seem to be reluctant to sort it out. They come across as rather aloof with a superiority attitude and this doesn't bode well for any owner of a bit of kit from them. The fact that it is the most expensive kit available by quite a large margin and users are willing to part with large sums of money to buy accurate and long lasting kit, says a lot for their reputation and marketing. It takes a lot to build up a good reputation, and even longer to become a top seller when there a lot of cheaper options available and you are still shifting large quantities of your goods. To have a 'we know best' attitude and ignore user problems isn't a good way to deal with these issues and may eventually bite them on the bum!
With regard to the domino/Seneca combination and the alignment /gearbox issue, I find it rather strange. There is a 2g difference in weight so that cant be the problem. No one has said the Seneca adaptor is badly made so I would think that there is minimum run out when it is spinning and it would be out of balance or causing excessive vibration if it was. The difference in rpm between the two models isn't that great and these machines are designed/ made with pretty good tolerances as stated before, not everyones leccy is the same, and this is taken into account. If the rpm is a couple of thou down the user would just move it a bit slower, as anyone who uses a router would know to slow down when using a bigger router cutter as opposed to one of a smaller diameter. The Seneca adaptor has been available for several years and probably have sold quite a lot of them. Why has it suddenly become a problem? Surely if it wasn't suitable this would have become evident from the start and Festool would have issued a warning when this problem first appeared.
The only conclusion I can come to is that they wish to sell both models rather than just the one and this is there way of ensuring that users who need to use both sizes buy both models. Not a good way to do business in my opinion, but then this isn't the first time they have been caught out. Anyone remember the price fixing issues of a few years ago?
Mike