Can you use a domain name that includes a product or company name from another company?
For example, could I register a domain starbucks-reviews.com and make reviews of starbucks shops? Or ipad-portal.com?
Or would that be a legal issue?
This is kind of a complicated topic and has been challenged on various free speech issues, etc. You can clearly register the domain if you choose to. The question is whether or not the trademark owner will be able to take it way from you if they so choose. The issues around this are available here.
Aside from the domain itself, then there is what you are doing relative to text and logos on the underlying web-site. This gets more directly into the area of trademark law, free speech, and fair use kinds of issues.
If what you are considering here is a key element of the strategy of the business, you definitely want to talk to a lawyer first. On the other hand, if it is sort of a "gangster" type competitive move and we are strictly talking about the domain name pulling traffic you can probably go for it as long as you are comfortable with the potential/likely encounter from the trademark holder and/or their lawyers.
EDIT: One follow-up thought/suggestion relative to your question is to consider the registration of common misspellings of the competitors domain name or other likely names a customer might type in that are not covered by their trademark or brands. For some supporting evidence this might bear some fruit, check out this article.
The bellwether for this is if you attempt to commercially benefit from the trademark holder's name.
You can register "starbucks-sucks.com" and as long as you do not make money off the site you should be ok.
You cannot register "indentical-starbucks-coffee.com" and make money by selling your own product using the trademark you do not own.
That's how it works in theory anyway. It all depends on whether the trademark owner is aggressive enough or not. Ask anyone that has dared to set up sites to criticize Apple Computer (or post pictures of prototypes). There are also international law aspects (WIPO-related stuff) and also the ICANN's own guidelines for taking domain names away.
One example here: http://www.theregister.co.uk/2009/07/28/wipo_free_speech/
It is not a good idea to use any trademarked words in domain name. The only save thing you can do is to use the words in other parts of the URL.
If you're talking about doing something that you hope will get attention, it's probably not worth it.
The question isn't really whether you have the right to use it. The question is whether you have the resources to defend yourself if the rights holder decides they don't like you using it. If you are bootstrapping with such meager resources that the questionable PR value of a derivative name is appealing, you almost certainly can't defend yourself if you achieve enough success to be noticed. You'd basically be setting yourself a landmine that will go off exactly when you're on the edge of real success.
On the other hand, you could plan from the beginning to lose the domain, but not without a fight. So perhaps you're trying to (for example) put together a general reviews site; you could start up a farm of subsidiary, domain specific sites which feed reviews to the parent site. When one of your subsidiary sites gets sued, you might be able to get some PR benefit from the legal proceedings, which could drive traffic to the parent site. That's a pretty risky strategy, IMO, because you could lose the lawsuit and end up getting shut down. So unless that (or something similar) is your plan, I recommend against using domain names derived from trademarks.