The heart of any Blockchain venture is the consensus algorithm, which you may evaluate based on:
a) what security properties it provides
b) what is the level of decentralization & diversity it allows for
c) what is the cost / effort / incentives of participation & operations
d) which are the attack surfaces & probabilities
e) what is it´s performance & scalability, stability (forking)
f) what assumptions & limitations does it make to allow for the previous statements
g) what kind of proofs exists for the previous statements
In this context I believe Algorand outperforms Cardano as you can´t really get more decentralized & efficient then the Algorand protocol.
However of course there are many other aspects to a Blockchain, than the consensus, so we shall see more from Algorand in the future to be able to compare.