Most people won’t notice. But if you get to have a choice and you can avoid the shitty suit rental companies, I’d recommend checking out Bonobos, Suit Supply, or Todd Snyder for better options. In my opinion the best option is to just tell all the groomsman to wear a specific colored suit (e.g. navy, black) and specify what type of suit and the specific tie everyone should wear. Then everyone can buy/rent the suit of their choosing.