Yes actually very helpful. My original plan was to do this, but the way my anes rotation works is, every day I work with someone different. There are 2 possible attendings I can ask for a letter.
One is my advisor, with whom i've only worked on one occasion during the past 2 weeks and once about 1.5 years ago during MS3 (which he didn't remember). But he will be getting the evals from all the people I worked with over the past 2 weeks (I think).
The other attending I haven't worked with at all yet since he's at another site, but I will be at that site the next 2 weeks, and I will be working one-on-one with him tomorrow (Saturday) the whole day. He offered to write an LOR for whoever volunteered to work with him this Saturday, and he'd prob write a nice letter, but prob is, since he loves students so much, a lot of ppl ask him for letters. And since he doesnt' know me that well, I'm concerned that it'll just be one of his extremely nice, gushing "form" letters. Also, it just feels more that he'll be writing this letter in exchange for my coming in, since he promised this in advance. This makes me think that this letter might not be as strong as it would be from someone who writes one because they are really impressed with me.
Any advice?