The pad you get also depends on the type of player you are. If you're not a hardcore snare player, a pad like the Invader may not be necessary for you.
For instance, I'm a tenor player. Now I've got a tenor pad, but I really wanted something I could put in my backpack and take with me. I've tried out several pads, including the Invader, but I went to Guitar Center last weekend and bought a rather generic Vater two-sided practice pad for $30, and I love it.
Finding the pad you like is almost a matter of trial and error. It's like you're trying out different mattresses until you find that one with the sweet spot - the one you'll just fit right into. Get what I'm saying? Make sure you find the right one. You will be spending a lot of time with your practice pad, believe me.
