Determining whether a particular password is "strong" is an imprecise exercise. A slightly better question is whether it's strong against a particular type of attack. This provides a framework from which you can start to evaluate how many guesses or how much time is consumed trying to match guesses to your particular password. But this also forces you to make some assumptions about what attacks and approaches will be tried, and these might not match up with what would happen in the real world.
So, looking at your two presumably randomly generated passwords we can say that the obvious attack is to try all possible random combinations with their respective character pools. We know if we try all combinations we will find a match at some point during that search. We could also evaluate how exactly the guessing software iterates through the random strings and estimate where within the overall brute force process those passwords are likely to be cracked.
Just to make up numbers, let's say your first password would be matched 4% of the way through a brute force of its respective keyspace, and the second password would be matched 39% of the way through its respective keyspace. You could take those results and accurately say that the second password is stronger against this specific type of brute force attack.
But this couldn't tell you that either pool of characters was better or worse at producing secure passwords. It is limited to comparing those two specific passwords. On average both pools would produce random passwords of approximately the same strength since they have a similar keyspace.
We could also look at the computational feasibility of an attacker exhausting all possibilities in a brute force of either keyspace and say that today it isn't likely. At one trillion password guesses per second it would take over 600 days to exhaustively search either keyspace. If neither is likely to be cracked then you could argue they are equally strong, or at least both strong enough, from a practical standpoint.
Another attack might be guessing dictionary words. It's seems safe to say that neither of these passwords should appear in a dictionary. In this case they're also equally strong, since neither have a chance of being guessed.
However, if we step back to evaluate the likelihood of their respective keyspaces matching dictionary words we might see a different result. Your first password's keyspace is made up of around 0.27% strings that are all lowercase, all uppercase, or a mixture of alphabetic cases. In comparison, your second password's keyspace is around 14.45% of those same strings that could be dictionary words.
Now that certainly doesn't mean all these alphabetic strings are words (or combinations of words). A very, very small percent of those strings would match any given word list. But you could make the argument that a higher possibility of a randomly generated password from the second pool containing only letters means that this pool has a higher chance of generating passwords that match words. I'd urge you to actually measure this effect with word lists before proclaiming this to be true, but some people might see this and say that the first pool generates stronger passwords.
So my conclusion would be that there are different ways of measuring the strength of these passwords (and I only discussed a few). Depending on which approach or approaches you took you might get different results.
