I voted "not at all" because initially everyone was incredibly gentle and helpful with me.
A year later, there are a couple of seniors of whom I've become somewhat wary: the ones who (to put it positively) will challenge me to stretch my ukemi abilities when we practice together. Intimidated? I'm not sure. Maybe a bit. I do know that next time sensei says "Try resisting the koteoroshi a bit to make sure partner is doing it right" there is one student I'm not going to try that with.
I've also gotten a lot better at looking at them and seeing how good they are, which is (in a nicer way) a bit intimidating in itself. I really got a lot out of the belt testing session because it laid out the whole progression from fifth to first, and you could see just how much was demanded of the higher ranks.