The CS4 is my main compressor and is on my bench inside the house. The power supply is mounted under the bench out of the way, so it's not really convenient to move. The L3 was on sale for $200 off plus an additional $40 off with the coupon and it's completely portable so I can take it with me anywhere I want. I have a neighbor who is just getting into PCP's and he's set up a longer range in his backyard, so it's easier to carry this next door and not have to worry about extension cords when shooting with him. And, as Gary pointed out, you can's have too many toys!