A:Answer Keeping it plugged in will enable pushing it to its limits, since you never have to worry about battery life, but if portability is not a concern, why not get a desktop instead? You will get more computer for the same money (or get the same computer for less), not to mention more, and easier upgradeability, even going up to 128 GB of RAM if you want.
Weight wise, it's probably about average. I've seen gaming laptops at about 4 lbs. and at 8 lbs. The lighter ones will generally cost you more money (the 4 lb. one I saw was around $3500).