I agree with Bill, but looking at the first post again, I think the OP already made up his mind to get a densitometer. Many things can be used to avoid this purchase (step tablets, modified spotmeters and some enlarger meters for example), but nothing beats the real thing.

I have used Agfa, XRite and Heiland. The Agfa was great, but it had problems with measuring inkjet prints due to its 'color blindness'. XRite is very popular and easily available used, but mine needed frequent calibration, and XRite charges a lot of money for factory calibrations. The Heiland served me well, it requires little or no calibration, and Heiland even made me a custom units, because I wanted a special function to read absolute reflection densities.