Yes...the best advice is to compare them at home in your system; that is the only way to know. I can tell you only about the Powerbloc2 based upon recent hearing. It's amazing and at such a low price I cannot believe what it puts out there in terms of overall musical enjoyment, sound and imaging.
For me it's not Class A as I've always preferred the magic of a great A/B design. My current Esoteric A-02 has a broad power range in Class A before switching but either output range and amp mode provides amazing sound for the money. I may pick up a Powerbloc for comparison and if, not when I also bring a pair of Legacy Valor into this system, I'll need more amps and for that, the Powerbloc is an inviting combination of sonic excellence and price/value!