I bought a Dell U3011 30" monitor on Craigslist recently for $600. This was originally a $1600+ monitor.
It has a DisplayPort interface as well as HDMI. It works fantastic with my 2011 Core I7 MBP and also my current-gen Apple TV.
Dell has some good products - this monitor puts the Apple 30" Studio Display of the same era to shame. Once my brother (graphics systems professional) digitally calibrated the monitor, the color is balanced and text is sharp.
Dell also still gets a lot of respect from business in the server world - especially Windows Servers. They still offer 1 hour repair response for those that can afford it.
Problem is, everyone's moving to cloud-based CaaS (crap as a service). Companies buying (Windows) servers today are the same dwindling market that companies buying mainframes were in the early 90s.
Dell hasn't had a hit product since their laptops and desktops of a decade ago. None of their iPod competitors ever gained traction and they've had no successful phones or tablets.
In short, they are buggy whip manufacturers. They make stuff that less and less customers will want and have not offered any 21st century products that the marketplace wants to buy.
They kind of want to be IBM - offering 'business consulting services'. Problem is, even IBM is having trouble sustaining margins in consulting.
Meanwhile Apple chugs along, redefining industries and reaping 30+% margins on most products.
Interesting to say the least...