Unless you're on high doses of gear and pretty much anything you do works, getting a pump isn't a good way to tell if you had an effective workout, as others have already said.
To answer your question about high vs low reps, each has their place and one rep range is not better than another. Each should be looked at as a tool. With higher reps, you can generally induce maximum hypertrophy and achieve optimal total volume with fewer sets, and therefor less time in the gym. BUT by doing only this you won't make as good neural adaptations as you would have with lower rep sets, so you won't gain quite as much maximal strength.
Now, with low rep sets you need more total sets to reach an optimal amount of volume for maximal hypertrophy, but you will make better neural adaptations due to the higher weight, and therefor you will gain a little more maximal strength. You'll also obviously have to spend more time in the gym this way. 10 sets of 3 is going to take considerably longer than 3 sets of 10.
