If it helps further, there is also an old school method to measure ESR quite accurately using a known series sense resistor and a decent 5.5 or 6.5 digit DVM that can measure AC Vrms voltage up to about 100kHz. By measuring the voltages accurately around the sense resistor it is possible to calculate the capacitance and ESR of the capacitor at various frequencies up to about 100kHz. For critical testing of small, low ESR caps I'd expect this old method to beat modern LCR/ESR meters like the DE-5000. However, it is quite a clunky and slow method. I semi automated it using GPIB and a Windows app written in VB. Prior to this I did it using Excel or Quick Basic.
I've also used the Analog Discovery 2 to measure ESR with great results. It gives a swept result for ESR and capacitance from (say) 10Hz to well over 100kHz if required. For rapid testing, it is going to be difficult to beat the convenience of modern meters like the DE-5000 though. I'm quite tempted to buy one but I'll probably stick with the AD2 for a while longer. I rarely use the AC DVM method these days even though it can be very accurate and it also allows an external dc bias to be added to the capacitor if required. This can be quite educational when measuring small SMD class 2 ceramic capacitors where the capacitance changes a lot with dc bias.
