Sorry for jumping in, but can the 5000 measure in-circuit? Hkw dows it fare in comparison to the MESR-100? (I mean, am I getting more bang for my buck considering that I'm going to use it for checking lytics, polys and ceramic caps)?
Yes it can do measurements in-circuit.
But you do need to be aware that the DE-5000 does not discharge capacitors, so you'll have to do that manually prior to testing any capacitor (in-circuit or not). You'll blow the meter's IC if you don't (no protections, which allows for greater measurement accuracy).
The DE-5000 can test a lot more parameters as the MESR100 is just an ESR meter. It comes down to what you're after.
Just basic (?) cap testing on PC stuff: motherboards, GPUs, etc. I read somewhere that some caps are meant to be tested at different frequencies for correct reading, so I assumed I could get more readings from the 5000 since it isn't fixed like the MESR-100. Does it makes any sense or I can stick with the MESR? There's a 3x price difference between the two.
As for the discharging I'm aware of it, but thanks for the reminder.
The DE-5000 is capable of multiple frequencies (100Hz, 120Hz, 1KHz, 10KHz, and 100KHz). As per what frequency you'd want to test at, that will depend on the circuit.
For example, if you're doing a linear supply, you'd need to test at 2x the mains frequency (100Hz for those that live in 230V mains territory, while it'd be 120Hz here in the US/CAN). The closer you can get to the cap's operating frequency, the accuracy of your measured values increases.
In terms of price, I'm only seeing 2x for the DER EE DE-5000 v. the MESR-100. Of course, my searches tend to present US locations & pricing, so YMMV depending on your location.
FWIW, if you go into your user profile, you can set your country, which will then display your nation's flag beneath your userID. Makes it much easier for other members to post relative links for you in terms of pricing and availability.