Some of them will be every bit as good, some of them will be a waste of money. All depends on where you get them from really.
One thing I will say, is that if they're labeled as refilled, don't bother. They'll probably leak, smear, and clog up.
What I often suggest to people, is to get a cheap laser printer for all their B&W printing, and then keep an inkjet around just for color stuff. Even the half-filled toner carts that come with laser printers should be able to do around 2,000 pages, which is significantly more than you could do with any inkjet. You just can't beat laser printers on a per page printed cost front, or overall quality of the output. Laser printers also tend to last significantly longer. At my last job, there was still an old HP LaserJet II that was still in service after probably over 10 years, and it worked great. If you're going to invest in a printer, I'd invest in a laser. Inkjets are cheaply made toys in comparison.
I am looking to buy replacement ink cartridges for my OfficeJet 6210 printer. I see there are a lot of generic cartridges available for this printer that are much cheaper than the genuine HP cartridges. I am wondering if these cartridges are okay to use or if I should stick with the HP cartridges. Any information that you could offer me would be greatly appreciated.