Foils are definitely not twitchy. In general they are slow and more smooth. They can be more relaxing to fly, but depends on the conditions. In gusty conditions they can be much more difficult to fly than a tube. The smaller sizes are generally less stable, both structurally and because of speed. Because a smaller size is tended to be used in wind that is more gusty it compounds the issues they can have. That said they can be easily customized a bit to be more stable and easier to fly at the sacrifice of other attributes. The small foils have tremendous range , I can get 30knots range out of a 6m maybe even a bit more depending on style. One of the benefits of a foil that can not be overstated enough is the setup. Setting up a 22m vs a 6m is not that much difference. People would not even consider the setup on a 22m foil equivalent 25-30m tube, because it would just be so much hassle. Hence there is no such tube kites in the market and yet 22m foils are still sold.
I have found foils to flag incredibly reliably. I do have plenty of confidence to self launch and land in very high winds because of this. In fact I generally only self launch and land always. I think tubes would give more confidence riding. For me at least my riding on a tube is much easier and I guess higher level particularly kiteloops, except on a foil slack line surfing particularly in light wind which I love. Oh and riding upwind, height and hangtime which are all better on a foil did I mention range? The main benefit of a foil and what makes them fun for me is getting on the water quick and more often. They make conditions more accessible. You will be on the water earlier doing more, whether that be surfing, floaty jumps or even handle passes... You get upwind quicker so have more time to do tricks or ride waves when on the water. More range means not having to swap kites or being more comfortable for more of your ride.
I can definitely say more time on the water, makes you a better kiter and people would be foolish to disagree. I think foil kites give you more time on the water. What people often don't understand is the quality of water time you get with a foil.