I tried ds3 with some ripe banana in one and he sucked and gummed it right out (no mess! but fun to clean) his first real swallowed food at 23 weeks. They look great for slippery fruit/veg and frozen stuff for teething. My boy just wants to bite!
babyfeeder here
(I got mine from ebay for £5, a bit more colourful and the handle is a good teether too - someone imports them from Munchkins in the US)
Yes I did have to hold on to it with him.