We report on the performance of FLAMINGOS, the world's first fully cryogenic near-IR multi-object spectrometer. FLAMINGOS has a fast all refractive optical system, which can be used at telescopes slower than f/7.5. This makes FLAMINGOS a very efficient wide-field imager when used on fast small aperture telescopes and a high AW spectrometer using laser machined aperture masks for MOS spectroscopy. FLAMINGOS uses a 2048x2048 HgCdTe HAWAII-2 array by the Rockwell Science Center. The array is readout through 32 amplifiers, which results in low overheads for observations. We describe both the operating characteristics of the HAWAII-2 array and of the array controller and data acquisition system. FLAMINGOS has been in operation for about 1.5 years and is now in routine use on four telescopes: The Kitt Peak 4-m and 2.1-m, The 6.5-m MMT and the 8-m Gemini South Telescope. We will describe the operating characteristics of FLAMINGOS on each of these telescopes that deliver fields-of-view from 21x21 arcminutes to 2.7x2.7 arcminutes and pixels from 0.6 arcseconds to 0.08 arcseconds. While providing a large AW product for fast telescopes (i.e. f/8), FLAMINGOS becomes progressively less efficient on slower telescopes. Since nearly all large telescopes have fairly slow optical systems (f/12 or slower) the combination of large aperture and slow optical systems makes FLAMINGOS ill suited for optimal performance on current large aperture telescopes. Thus, we are beginning construction of FLAMINGOS-2, which will be optimized for performance on the f/16 Gemini South 8-m telescope. Similar to FLAMINGOS, FLAMINGOS-2 will be fully refractive using grisms, laser machined aperture masks and a 2048x2048 HgCdTe HAWAII-2 array. FLAMINGOS-2 will provide a 6.1 arcminute field-of-view with 0.18 arcsecond pixels. FLAMINGOS-2 will also be designed to except an f/32 beam from the Gemini South MCAO system.