First impressions do count but I think the above poster has a point, a suit can actually harm your chances in an environment where no one wears suits.
My expectation is that turning up in a suit would get better results. The effect is probably smaller in hard-skill roles but I'd assume still present.
These are just instances of my point (a): not having a clue about SV work culture.
> there are even people who wear suits all the time
Not in silicon valley tech. I mean, sure, maybe there's one guy and the number is not zero.
Turning up in formal business wear isn’t going to be a positive social cue if everybody you interact with is dressed casually.
The social cue you’d be giving off is that you stick out like a sore thumb and probably didn’t do your research on the company before you showed up.
Literally no different than turning up to Lloyd’s of London in a Hawaiian shirt and Bermuda shorts.
So then by your own admission, the best way to come dressed is the same way your interviewer tends to dress.
Which is essentially what most people in this thread are arguing for - dress to match the company's culture.
There are many ways to wear a suit. If you walking in wearing a suit that doesn't fit, doesn't suite (no pun intended) you, and it obviously makes you feel uncomfortable then that could count against you. But you walk in wearing a suit that fits, makes you look good, and that you are comfortable wearing, then I have a hard time seeing how it will count against you.
If an interviewer can't tell the difference between a flex and show of good intent, they probably should go back to jobs where they don't need to make judgements of character.
If you forgive me the analogy, and assuming you're American, would you think of checking the etiquette of entering into a shop? In the US, the concept itself is weird, you go in, buy stuff, and leave. In France, you must greet the shopkeeper right as you go in through the door. In Hungary, you must wish the shopkeeper a good day in reply to their greeting. It's simple... if you know it's even a thing you should check.
As long as suits and ties remain the uniform of politicians and managers, I don't think techies will ever willingly adopt it for themselves as well.
Being hyper judgemental about the clothes people wear isn't productive
However, like it or not, it is a signal because it means you deviate significantly from the mode of the distribution. And a sober application of Bayes suggests that if anything, all else equal that signal is a negative one.
Admittedly I thankfully wasn't in the SV bubble where people are wound this tightly about it!
I personally dress like a hobo when I'm out and about, and wear a uniform of jeans and a blue shirt when I go into the office, so I really don't care about the suit either way. I'm wearing it for your benefit, so if you don't like it, just tell me upfront - don't make me guess if the job isn't about mindreading.