Went for a week on my own and loved it. It was late in the year so it wasn't scorching but it was still beautiful weather. There are sandy beaches, on all three islands (though I'd agree that it tends to be more rocky than sandy there and the best to visit is probably the Blue Lagoon on Comino which is a tiny island between Malta and Gozo). Food is pretty variable, I had some delicious meals and some less interesting. In terms of sightseeing the place is full of interesting things to see from underground temples to medieval walled cities to some of the most unusual countryside in Europe. One thing I noticed though all through the islands is that the kerbs are very high, if you have a child in a pushchair or a small child it will be very tiring.