Suits VS tuxedos for a formal wedding?

If you're requesting that your guests wear tuxedos (which is basically what black tie optional means), then I really think your groomsmen should be in tuxedos.

It will be much cheaper to rent a tux than buy a suit. Ours were about $150 to rent. I think you need tuxes. GM should be dressier than other men. You could always offer to help with the cost.

I think it's totally doable to have them in nice suits, have them buy the black pants, jackets and a white shirt and get them the ties, but if you want it to be more formal then I would definitely see how much a vest underneath the jacket would cost. My FH only paid $60 for his pants and jacket and $20 for his shirt for his sister's wedding last year and I'm pretty sure we'll be re-using that same suit for our wedding and purchasing the ties ourselves. Overall, if you add vests it would make a big difference than just having the ties. Hope this helps

Considering your groomsmen are either fresh out of college and/or in entry-level jobs, IMO, a black suit is sufficient. Most people say when the invitation says "black tie" female guests must wear a long gown and men must wear a tux. What if your guest doesn't have a formal gown or a tux? Would you rather they decline the invitation, or wear their best? When I was younger, I didn't attend several weddings because the couple had a black tie wedding and could not afford to purchase a dress AND a gift.

ETA: Agree with Kelsey. A vest will definitely "fancy up" the suit.

There is nothing wrong with black suits at a formal event. That said, good quality black suits can be pricey. Depending on fabric quality, many are easily more expensive than renting a cheap tux. You have to find out the GM's budgets and then see if you can find a black suit within that budget.

Also, if your GM are wearing suits, I would not put "black tie optional" on your invitation. It is wrong to put pressure on your guests to come dressed in black tie when the GM won't even be following that standard. Just leave off a dress code.

Reiterating what Emily and 8815 have said-- its okay for them to wear formal suits, but you should definitely not tell your guests its black tie optional. They will feel like idiots if they show up dressed more formally than your bridal party. If you must suggest a dress code (which should be done on a website or through word of mouth, anyway, and not on an invitation), I would suggest using "semiformal or cocktail attire".

http://www.emilypost.com/everyday-manners/your-personal-image/69-attire-guide-beach-casual-to-white-tie-

(though, keep in mind that purchasing a good suit will likely be more expensive than renting a tux or suit)

Like has been said if you are asking yours guests to wear black tie, your groomsmen should be in black tie, which means tuxes. You have two options change your dress code to semi-formal or keep it black-tie optional and have your groomsmen rent tuxes which will likely be cheaper for them.

I like tuxedos for the groomsman and suits for guests. I want them to be a little bit more dressed up.