To measure a 20MHz signal reliable you need to sample at least twice as fast so 40MHz. With the 1010 you can properly measure 3 20MHz signals at the same time, I think that 6 channels will be pushing it.
What is the max. output frequency that your boards can provide. An AVR based board will never get above 8MHz, I do not know about the others.
But I doubt that you need something better than the 1010 for your intended use. Just enjoy it.
I'm happily using one of those cheap 24MHz logic analysers for AVR development: USB Logic Analyzer - 24MHz/8-Channel - SparkFun Electronics. And if you shop around for the cheap Chinese stuff you can get them cheaper.