I’m a High5 fan, mainly because you can buy them incredibly cheap online, but also because they are easily digestible and taste fine to me.
Done all my marathons and triathlons fueled mainly by them. Compared to trying to chew down a partially dessicated slug which some others can be like, they’re delicious!
I get them either in this format, or this. Slightly different mix of stuff in each.
However, gels are a very personal thing, what works for some won’t necessarily work for someone else, so I’d suggest trying a few and see which sit on your stomach OK and you can face consuming when you’re needing to get the calories in but don’t actually want to eat anything!
Cheers, Rich