I’ve worked in the tux/men’s wear business off and on (currently on) for years. So I can throw out a couple of things. First, there’s definitely nothing wrong with doing suits, especially with your time, style, etc. We’re actually doing navy pants and beige sportcoats for our 2 pm wedding. It’s more a matter of your own style, whether yoy feel comfortable with it and all.
Second, I agree with what was mentioned above in regards to fit. A rental tux never fits as well as even a halfway decent suit. It just can’t be tailored properly. Especially if any of the guys in your wedding have “odd” body types (like the above mentioned broad shouldered small waisted fellow), you may be a lot happier with the look of suits.
Thirdly, they can be pretty reasonably priced, depending on where you get them. Some people consider Men’s Wearhouse a little high. They do have good sales tho, especially on multiples. I would actually recommend S&K Menswear if you have one near you and are on a budget. Not GREAT quality, but very good (unless you do the 100% polyester suits. Don’t. They’ve come a long way since the 70’s, but still, trust me on this one.), and great prices. Probably not where I’d send a high end businessman, but for a younger guy starting out, or for something like this where you need several at decent prices, it’s a good idea.
Major drawback to me is that navy comes in a thousand different shades. Black actually does too, but it’s somewhat less obvious. If you have them just wear random navy suits, they may looks just a little off kilter in pictures. As someone in that business, that’d bother me. You might not care. Personal decision there. But if it IS a concern, you’ll have to insist they all wear the same suit from the same store, and if they already own a navy suit, that could lead to some fights.
Also, side note to that. I HIGHLY recommend wrinkle-free shirts if you do suits. Especially if you can go to an S&K. They have good sales, and it really truly makes a world of difference in how nice they look, espcially if they take their jackets off.
And just for the record, I do actually work for Men’s Wearhouse now, so you needn’t worry that I’m just pushing S&K to drum up business. ^_^ And good luck! I know it’ll be beautiful no matter what you decide!