They will end up with similar feature set, so unlikely both will be successes.
The main problem for XCP seems to be the lack of funds. Even though XCP has shown more competent developers, competing over a long time against MSC with lots of funds is difficult.
there are at least a few hundred early adopters and burners who have interest in xcp succeeding
additionally the developers say to be self-sufficient and had until now no problems even to fund premium auditing - I assume they did not create counterparty protocol to become rich
no doubt msc has more money (even though we do not know, but it is highly likely), but why does it need >1000 btc to develop and run a protocol on top of bitcoin?
It helps when you have to hire a lot of additional developers to make several features in parallel.
A few hundred early adopters and burners doesn't translate to funds for bounties.
I am not saying MSC will be a definite success and XCP a failure. If it was I would have sold XCP now and bought more MSC. Just what I think may be a likely outcome.