Lemon balm makes a terrific tea and I like it even better in tea blends. It can also give you great lemon flavor in dishes where you don't want extra liquid or acid (like lemon juice would give you). For instance, it's easily added to a butter cookie recipe without needing to alter the liquid volume significantly. It has a slightly softer, sweeter fragrance than lemon verbena (the most lemony herb I know).
It is in the mint family, so certainly can be invasive, and looks like a mint family member. Like others in the mint family, it seems to like a bit more even moisture than most herbs, but it's not terribly picky. It prefers some drainage, but can usually tolerate being a little soggy (compared to most herbs). It can also tolerate some shade and prefers it in my area of extreme heat. It won't really appreciate poor drainage, constantly soggy soil AND lower light, though. It is pretty cold tolerant, but I'm not sure to what zone. It's more than hardy to my area, even in a pot, as long as it's kept at least a little moist.
I grow mine in a large pot, but it doesn't appear to be quite as root aggressive as my other mint family members. Any of the mint family can spread readily by seed as well, so beware. I don't have experience sprouting it, as I bought a plant once and haven't yet needed to sprout the seed I bought when I thought I had lost that plant.
Hope this helps!
USDA zone 7b/8a (depending on the year and microclimate
), AHS heat zone 8-9, Eastern Crosstimbers/Grand Prairie ecozones