Methyl B12 is claimed to be better than regular B12 (Cyanocobalamin).
B12 is better absorbed under the tongue (sublingual) rather than the oral route.
In my experience, I know that B vitamins metabolize quite fast, e.g., a few days. So, if you have a deficiency, then taking that vitamin should be noticeable. For instance, I experienced some horrendous panic attacks with fatigue, I used a nasal form of B12 and the results showed up within 24 hours, I was much better. If you have adequate B12, then results will not be as noticeable.
I use this as a good test to see if my theories are correct about deficiency, rather than taking for a prolonged period of time.
Keep in mind that B12 can be stimulating for some people, I know some people that had panicky feelings after taking.
Usually, it is better to take a broad form of B vitamins. The reason is that nutrients can play off one another. So too much B12 may deplete folic acid (which is a good partner to B12). Other B vitamins are necessary for metabolic functions.