Hello Kenny,
I have both the Heller and the Airfix LCVP's. The kits are from very old molds, the hulls are quite nice, but you will need to do some major detailing to bring them up to the level of detail of
the Dragon or Trumpeter LCMs. I also recently picked up a
Pegasus Hobbies  LCVP in the same scale...very rough
kit but the 3 crew and 18 combat figures are just awesome.
I guess if you are doing a landing scene, you can always use the less detailed kit  in the background or as a destroyed craft or then again superdetail !
Have a nice day and happy modelling! 
