I use KAL magnesium glycinate. IIRC, bisglycinate means it's bound with 2 glycine molecules. I find that I respond best to using 2 forms of oral magnesium- magnesium malate and magnesium glycinate. Mag Malate is excellent for energy and muscle pain. Mag glycinate is very relaxing. I use the mag glycinate at night for this reason.
If you have problems swallowing large tablets, you can use the capsule forms which are a lot smaller but you usually need to take more.