Is it really that good?...
Well, you need to consider that the sail can only really be used in near perfect conditions (i.e. low wind speeds); this is one of the factors that makes it so enjoyable (no storms or bad weather!) and you need to appreciate that you are not going to be sailing a racing yacht.
Another factor is that, of course, there is the increased risk(challenge) of being capsized which, in the North Sea in winter or summer, may not your ideal way of spending your weekend
Finally, if you are expecting to always be able to use the sail on your cruising expeditions the wind direction on a given day may not work in your favour and in those circumstances pedalling will probably be a lot faster (because you can travel directly to your destination).
That said, The Adventure with the sail kit and daggerboard (no I don't personally use outriggers because they take away part of the challenge and enjoyment for me of sailing a 'proper' yacht) is probably the most entertaining boat I have ever sailed.
Hope this helps!