Which one do you prefer? I personally like the fallout new vegas version because of rapid fire, however the fallout 3 version can damage more enemies with the "Shocking" effect that allows the electricity to cover a small ares (No need for a direct hit to kill/damage enemy).

Both are useless in my opinion.

I prefer NV because it causes damage over time without being too overpowered. The power is balanced by the fact it decays rather rapidly.

Fallout 3's is a little more accurate and New Vegas' deals a little more damage.

With that being said, the Tesla Cannon svcks regardless of which game it's in. I'd suggest picking up a Gauss Rifle.

I kinda like the prototype from NV. I wouldn't use it as my main weapon, but it's a fun little toy.

3, the tesla in NV is about as pointless a weapon could be. Its heavy, ammo inefficient, damage per shot isnt special, its DPS isnt that great, not too many perks affect it in a game changing manner. (Compare this to say, a brush gun which benefits from perks, is similar in weight, has great one shot damage and acceptable DPS) Then again, one of my few complaints about NV has always been how badly energy weapons were implemented, ESPECIALLY the vanilla ones. (DM holorifle, OWB LAER;they ditched the ammo mechanics, upped the damage, and allowed for useful mods, GRA has the tribeam of death combined with a certain weapon with a power rating OVER 9000!!!!!)