I got these speakers when I moved because I didn't want to pack/wanted to upgrade from my companion 3's.
First off, the good. These sound fantastic. If you had your eyes closed you'd probably think there were 4 speakers. Bose is always the best when it comes to great sound in a compact package. These are great for small desks and rooms, because they take up so little space and have a lot of sound.
Now, the bad. The companion 3's had a 3.5mm input jack on the back of the sub, and a 2nd on the corded control. The 5's have a USB input on the sub, and a 3.5mm on the control. Now, in many cases I can see the USB being fantastic. It's probably better quality, and on a desktop computer, you have a million USB ports on the back of your tower. I, however, am using a desktop replacement laptop, and one thing no laptop has in spades is USB ports, I have 4. Also, I find the whole setting up of the USB control overly difficult, I like just plugging in the 3.5mm jack. So that's what I did, but now my remote has two cords coming out of it (the control/power cord and the 3.5mm cord to my computer) which is kind of a bother.
My biggest problem though, is the power saving mode. My companion 3's had two settings, off and standby. If you wanted to listen to something, you tapped the control, and the light changed from yellow to green, and instantly you had sound. When you're done, you tap it again, and they're on standby.
On the 5's, that still applies, BUT, if you go long enough without having sound (ie, I'm just browsing the internet) they go into a power saving mode (light turns red) and you have to tap it again to turn them on. The kicker is that it takes about 5 seconds for the sound to come on. This wouldn't be so bad if the power saving mode didn't kick in WAY too fast (roughly 3 minutes). I tend to browse the internet a lot, and I come across a video, watch it, then go onto other stuff, find another video, watch it, and low and behold, no sound! I hit the control, the light goes green, but by the time the sound actually comes ON, I really have to restart the video. It sounds like I'm nitpicking, but it's annoying.
They also get a knock on the value for price part.. you pay a lot, and you get a really good product, but it's not what I'd call a real deal or bargain. It's kind of like buying a BMW or Audi. You get something great, but you pay for it in full.
My last problem with these speakers is the corded control. It's basically a thick disk, with an outer rubber ring you turn to change the volume, an a pressure sensitive topside that you tap to turn the speakers off and on. It also has a headphone jack and a audio in jack. My problems are these: 1, the pressure sensitive top is very sensitive, and if you have a messy desk and something happens to touch it, well, you get the idea. 2, the subwoofer volume controls are on the back of the sub. This is something I like to adjust as I live in a dorm, and there's hours of the day it's acceptable to have some bass, and then some where it isn't. Same goes for anyone living in an apartment, etc. I like to have the (rather large) subwoofer out of the way, which means that control is out of the way as well. I wish it was on the controller, after all, that's what the controller is for.
Don't get me wrong though. As much as I complain, these are very fantastic speakers. My pros section is much shorter than the cons, but the pro section contains the most important part, the sound quality. I love these speakers and wouldn't go back to my 3's or any other speaker system I've owned. There are things that are much better value, I'm sure you could get an almost as good set of speakers for $200, but the key word there is almost. These are among, if not the best, desktop speakers you can find that are reasonably sized.