I would steer you away from Mens Warehouse, and here is why. Mens warehouse is more of a "bargain dealer" of sorts for men with little time and are only putting on a suit because someone is forcing them to (for work, a wedding, and interview, etc). People on this forum will tell you they are poor in terms of cut, fabric, style, etc. (or just yell kill it with fire). Personally I think they can make you look fine, but you won't be as comfortable or as happy with the clothing. The deal your brother got probably included polyester, fused suits and shirts with somewhat scratchy non-iron fabric. Ties are almost always silk and are less of a big deal in my opinion.
You mention that your suit is tight in the shoulders and arms, which makes me think you and I have similar problems with suit jackets. I am likely not as muscular, but I do have very broad shoulders and a 9-10 inch drop (i.e. the different in my chest and waist measurements, for example 44" chest and 34" waist). I often have issues with mobility in cheaper suits and cannot easily make a "hugging" motion and it drives me crazy. I have less issues in the nicer suit jackets. I believe it has to do with cut of the jacket and it's construction, canvas (fabric lining inside the jacket) construction is more mobile than glue (used to create fused jackets). A %100 wool suit will also breathe much better than a synthetic one. I once wore my brothers polyester sport coat to a New Year's Eve party and sweated through my shirt in 30 minutes. You are likely right and the more slim fitting models will not work for you, so you are likely going to want a more traditional fitting suit (Brooks Brothers Madison Fit as an example) and then have it tailored. The pants will certainly have to come in at the waist, just try and stick to pants that aren't more than 2-3" off. Flat front pants are preferred, but in a suit, pleated pants are acceptable as well.
If you are in a big hurry to get something quickly for an event, then Men's Warehouse is a quick fix, but if you are looking for a more long term investment (as I assume you to be) I would recommend the following:
1. The tie honestly doesn't matter too much, stick to %100 silk. You can get them cheap off of tiebar. If you want something more elegant, you can upgrade to Brooks Brothers (wait for a sale) or even drakes, but I would not spend a lot of money here.
2. Shirts, start with white and a light blue. I am personally picky about my shirts, but the Brooks Brothers luxury line hold a good price/value point for me. If you wait for a sale, you can get them for ~$85 a piece and their non-iron fabric is actually very nice. I have both non-iron and iron versions, and they are very comparable. If you have larger arms, I recommend the regular fit and have the waist taken in.
3. For the suit I retract my ehaberdasher suggestion as they are a trimmer fit. Kent Wang can still make a MTM (made to measure) suit for you in your price range with any dimensions you wish. The ebay option works well (and I have done it in the past), but the trousers will almost always need extensive alterations. If you wish to try the ebay route, get your measurements down and look for a good deal on a new or "pre-owned" Oxxford suit in a classic cut (still stick to charcoal or navy). They have a special stiched armhole for good mobility and are extremely well made, their only downsides are (1) their styling is not always fashion forward or exciting and (2) the trousers (again) will need major work.
For example: I bought an Oxxford suit off ebay for $180 then spent ~$200 on tailoring everything (sleeve length, letting out back, finishing inseam, taking in waist, etc). So $380+dry cleaning for a nicely tailored suit, it isn't MTM/bespoke, but it is pretty darn good for a sub $400 suit. The Kent Wang option will save you some hassle, but the ebay route may save you some change. Your call there. If you do go the ebay route, get your measurements down (go to a store and try on some coats if you have to) and don't be afraid to ask the sellers questions.
You can also search the Buying and Selling portion of this forum for good deals on suits, shirts, and ties. If you follow the above, you should be able to stay within or close to your budget. These are however just my suggestions based on personal experiences, feel free to look around on your own and ask others.
I would start with a go-to white shirt, charcoal/navy suit, and whatever color tie you like, then build from there.
If you wish to search ebay, search the following brands as a starting point:
Oxxford Clothes, Ermenegildo Zegna, Brooks Brothers, Paul Stuart, Brioni, Hickey Freeman, Corneliani, Kiton
Edited by Gauss17 - 4/22/12 at 10:50pm