ESF is a very interesting mod, but good. Although its main focus is the popular DBZ series, I wouldn't hold it against the mod. The dev team made this mod as close as possible to the series, and it shows. For instance, the ability to fly, the ability to charge up and release huge balls of energy not to mention, you can control the beam midflight. You can even use the destructo disc, pwnage? I think so.
The models are well done, and the effects compliment the models well. Gameplay-wise, ESF is one damn hard mod. I was quietly flying around, minding my own saiyan buisness, until some person playing as Cell knocked me flying to the ground, and while falling, and lying on the ground, he manged to charge up a large beam and pretty much nuke me while I was lying on the ground.
Musically, the ESF Team decided a more punk approach, which isnt really my genre, but in most places it suits the mod. In my opinion, this is a must download for anyone who wants something new in halflife, rather than guns(now we have special beam cannons!).