So my question is, is a trusted forum reputation enough to trust someone?
Not really, only few trust feedback on this forum doesn't mean they're very trusted person. You can easily get trust feedback from DT member after you trade him (but not all DT will give it)
I don't want to judge the user who have trade with you, but like you said it's "small amount money", their rank and reputation in this forum is not worth to scam a small amount money. If you trade a huge amount money (like 0,01 btc above) and not using escrow, he can probably scam you.
You're right if you want to trade huge amount money with someone, you should use trusted escrow. Here are some few trusted escrow in this forum Few Trusted Escrow Provider