We feel that our kids are better off in the love of a big family than with lots of stuff.
So they don't have the latest greatest stuff, but do have a family who loves each other and willing to sacrifice stuff to have them here with us. I am not saying that you can't have that in a small family (we had 1 child for 6 years).
I think our kids have benefited and continue to benefit from have lots of brother and sisters. There are some things you can only get/learn from having siblings.
These things are more important to us that the latest toy or holiday.
Each to their own.
No I don't feel guilty at all.