Since you say you love the 50# bow, I will go out on a limb and assume you can handle it adequately. If so, you don't need to be especially eager to go up or down. String that sucker up and HUNT. This is a good hunting draw weight.
Going up to 55#, if that is your choice, may give you a slight edge in the hunting arena but could be a bit tiring on the 3D course or practice range, at least until you work up to it. (Just make sure you can still shoot with good form.)
Going down to 45# won't adversely affect your ability to hunt most commonly sought game, and it is more comfortable to shoot for extended periods of time.
If I were making the decision, I would go up. It is not usually that difficult to work up to 55# from 50# if your health is good. Just do so slowly over a period of several weeks.Can you shoot somebody's 55# bow a few times to get a feel for how hard you think it will be to get used to? If you think it is too much, then don't bother. After all, you do like the 50# bow that you currently have, so there is no real need to feel any pressure to change, unless you are like many of us and are looking for a good excuse to buy a new bow.