While they don't glide along with the ease of a two-wheeler, they aren't all that bad.
Still, if you are having hill trouble with the single speed bicycle, maybe some gears are in your future for the trike. I love my geared bicycles. I own only one single speed that doesn't get much use, but happens to be a great looking fat-tired cruiser, so it has its moments.
Do you have any friends with trikes who'd let you try them? You'll never know till you try one.