I played paintball a while ago and had amassed a collection of Montneel Icon Z-1s and Mega-Zs. Recently, my buddies wanted to play paintball for a 40th birthday party. I brought my markers, but figured the field rentals would be better than what I had. Much to my chagrin, they were renting Tippmann 98s (Sorry Tippmann guys. I won't use a tippmann). So, I told them I have my own and they kinda laughed when I told them what I had.
Long story short, I had to use my backup, STOCK Z-1 because my Mega-Z leaked air after a few chrono attempts. My buddies were saying that they saw me (because I had my old bright blue mask with yellow lenses) and they fired at me and watched their balls fall at my feet. And then when I returned fire, I was zipping them past their ears (I can't believe I didn't HIT them. I'm so out of practice!).
Like the OP, my kids are 10 and over and I want to go play paintball with them (mainly because I had a blast that weekend and remembered how fun paintball is). So, I'm looking at markers for them. The Azodin collection look very interesting.
As far as the tippmanns and spyders go, you can find a ton of them on Craigslist and for cheap (I saw 2 Spyders and masks for $50). Any other types of markers, you'll have to scour the for sale ads here at pbnation (or hope that a random one shows up on CL).