I’ve used CafePress a few times in the past, and I can honestly say that they’re probably not worth using if you actually want quality stuff. They are extremely handy/convenient for quick ideas or just doing things for fun, but overall you may be disappointed with the results. The items are certainly much too expensive considering the low/medium quality of the printed end product.
I have experience with a few of the products from various things I’ve made there.
Most of the t-shirts fade quite quickly after a few washes because their printing method is like a slightly higher tech iron-on transfer. Same kinda thing you can do yourself with those home kits, but a little more advanced. The prints look nice and last for a little while, but then they start going a bit crap. The shirt material itself (on the standard lower priced t-shirt styles) becomes a bit rough to the touch and seems to shrink/deform strangely after a while too.
On certain designs (lo-fi minimal stuff) the image fading can actually work quite nicely - gives the shirt an old/classic look almost. And the only shirt I’ve personally had so far which didn’t really shrink or lose its shape was the ash grey coloured t-shirts they have. Something to do with the blend of the material, the different types/colours of cotton or something, makes the grey ones stay quite nice.
I have noticed that they are beginning to offer some nicer shirts, such as some fitted styles made by American Apparel. The shirts from this company are really nice quality, very smooth and comfortable, much better than the standard shit from Fruit of the loom, or Hanes, etc. So, you can at least get a nicer shirt here, though the image will still fade, and you will also be paying another $4 or $5 overall.
Another serious disadvantage to their printing method is that they can only print on white or very light coloured things. The printers cannot reproduce the colour white, so all of your designs have to have a transparent white background. For example, if you print something on a yellow shirt, anything in your design which was white, will now be yellow.
If you don’t mind only making white/grey (or girly yellow/green) t-shirts, then this isn’t such a big deal. 
The big problem is that the shirts you get simply aren’t worth the money you pay for them. You’re gonna be paying something like $15 or $16 for a very basic quality shirt with relatively crap quality print on it. If you got it done by a professional place in a bulk quality (which I have done several times), you can get much nicer shirts, much nicer prints (real screen printing) usually for around $6-$10 per shirt depending on the complexity. Only problem there is you have to get a minimum amount, usually something like 50 shirts. But it really pays off in the end because the shirt you’re wearing simply looks beautiful.
The stickers they print come out pretty ok. I’ve had several batches of stickers for different projects printed at the professional level by companies (again, in bulk), onto very strong weather-resistant vinyl, etc. The Cafepress stickers don’t compare to the pro stuff at all, but they are still quite good. They still use a type of vinyl which is quite resistant, but it’s quite flimsy feeling and I don’t think it would last very long in the real world, hehe. The printing quality and colour comes out quite nice. A little faded or strange looking - simply because it isn’t real screen printing, but generally pretty good.
As with the t-shirts, the results are generally ok, but they simply charge far too much for what you get. You’re gonna be paying something stupid like $2.50 for a little 4" x 3" sticker, which is absolutely ridiculous.
They do posters as well, I’ve done a few test prints of these to check the quality. Same kinda story as the stickers. Paper/card quality and printing quality is generally pretty good, but the price is way over the top. Just not worth bothering with on a serious level. If you wanted to occasionally get a poster made from your own design work or something to hang on your bedroom wall, and you were prepared to pay a little bit extra for the unique print, then it would be ok. For mass printing on any level, they suck.
Finally (hehe), I’ve also tested the CD creation service Cafepress offers. This is one area where they could really be excellent if they just added a little more effort.
You can either mail them a master CD of your stuff, or simply upload MP3 versions to their site (max of 192kbps). Once all your tracks are in the system, you can design the CD case and all that stuff, by uploading images for the front cover, back, insides, CD face, booklet, etc.
You can choose between a standard jewel case with the usual stuff, or a very simple paper “sleeve” which is the same kinda thing driver CDs usually come in - simple bit of white paper with a clear window. The jewelcase CD is around $9 base price, and the sleeve is something like $5 or $6 - I can’t remember exactly. Anyway, this is one area that I feel they are actually being quite reasonable with. It is a GREAT feeling to hold your own CD in your hands, in a proper case with full colour graphics, etc. I got some CDs made for my Mars Wind project, and they just came out looking so sweet 
Surprisingly, they are very discrete about labelling the CD with “made by cafepress.com”. It is only visible in very small text around the center of the CD itself (where manufacturers usually put a serial number or something like that). They also add a very small barcode to the back cover of the case, but this just gives it a more profressional look for you, hehe.
It would just be nicer if they offered a better booklet with the CD. It’s only a very basic 4 page thing (front cover, back cover, 2 inside).
Here’s how the Mars Wind CD looks, if you’re curious:
http://marswind.com/marswindcd.jpg
Ok… sorry for ranting. I just wanted to give people a little heads up about Cafepress since I have a few years of experience with using them. In some areas they kinda suck, in other areas they’re pretty good. And the simple novelty factor alone from creating your own goodies can be a lot of fun to experience. But like I said, most things they offer are simply overpriced.
I dunno exactly what epresso.com offers, but just from quickly looking at their t-shirts and things, it looks basically identical to Cafepress. I recognise all the same types of clothing and things like that, so I am assuming that epresso is gonna be extremely similar - same kind of quality and stuff.
Hope this helps
Though it should be up to the Renoise team, if they too find this cool.
