Yes, you're taking on a bit more risk in the short-term... but everything's a trade-off, you're getting much back for a slightly elevated risk in having a short, concise, very meaningful (in our case) name that influences adoption. There's no other alternative -> .COM is a limited resource, only reasonable assumption is that reliability of other TLDs must improve in the long run.
Just because you're exposed to some reliability risk doesn't mean that you can't expose yourself to more by using a smaller TLD.