I also use abidec (have done since birth due to him being premature). We either mix in a milk feed or give directly in his mouth. I think it is quite bitter tasting but I think he is used to it as he's had it for so long, so mixing with something is probably your best bet. Just a warning, it is very orange and can go everywhere if they spit it out. It will wash out though
I also use abidec. It's the most convenient to get hold of. I mix it with her morning milk as i know she has the whole lot
We use abidec mixed in her breakfast, I know others use healthy start drops