Joy of Kosher's Table Decorations
Rosh Hashanah Machzorim: Koren Sacks and ArtScroll are two that I have even a little bit of experience with. I personally prefer the way the Koren Sacks machzor is organized and sounds compared to the Complete ArtScroll Siddur which I assume is similar to the ArtScroll machzor. Not only is the Koren Sacks very beautiful and white (fitting for the holiday) but it has fantastic commentary and footnotes from Rabbi Lord Jonathan Sacks, the Chief Rabbi of England. This will prove to be extremely helpful for people of all levels of experience. Also, the language it uses compared to the ArtScroll siddur is much easier to read and it actually sounds beautiful, almost poetic. In terms of size, the Koren Sacks machzor is about standard book size. I personally use and endorse this gem of a machzor.
However, the ArtScroll machzor is much cheaper than the Koren Sacks and I think it is not only translated but transliterated too (so you can pray in Hebrew while reading English letters). The ArtScroll siddur has lots of commentary too so I would assume the ArtScroll machzor does too. I will also give it to the ArtScroll machzor that it is a beautiful blue in color. I have seen them in person and I can attest to the fact that they not only look good in your hands but on your bookshelf too. In terms of size, I'm pretty sure the ArtScroll machzor is smaller than the Koren Sacks so while it might be a little lighter to hold, the print will also probably be smaller to read.
Both have their benefits and their downsides. Yet, both are put out by fantastic publishers worthy of respect. And just remember, if you don't like one, you can always try another! You don't just have to stick with one, you can always experiment and try different ones. As far as content is concerned, it will be roughly the same except the commentary will be different in each one. Sometimes, this is the appeal of one machzor over another.
The Kittel for Men: Since it is customary to wear all white on Rosh Hashanah and Yom Kippur, many men like to wear a garment called a kittel. They are sold at various Judaica stores but to help you start your search, here is what Amazon sells. Remember to get the right size! Also, it is inappropriate for a woman to wear a kittel since a kittel is considered a man's garment.