Jumping is for pansies. There is almost no good reason to take a jump equipped 'Mech since that weight is better put towards weapons or armour. Unless you're planning to set up a really clever trap, jumping 'Mechs will almost always die too quickly to be of use. Mech with jump jets. What a total waste.
Energy weapons kick ass.
As much damage as gauss rifles and heavy ACs do, they have very limited ammo. On longer missions or missions where there are a lot of enemies, you will love your ER PPCs. If you have a refit truck or Mech Bay available, it's not quite as critical. Choose your range carefully. If you know what forces you will be up against, choose your own forces to suit.