I've owned/used pretty much all of the MPCs aside from the 5000 and I say that the 4000 is hands down the best. The sample quality is about as good as it gets (for now) and you can always go lo-fi if you want by sampling lo-fi material or processing your samples... so you can have the best of both worlds. It also has tons of great features.
I honestly don't know why the MPC 60 is so hyped. I mean it's okay and all, but it isn't this magic machine that makes anything you make sound like golden era boom bap. To be honest, I find the sound of the 60 smooth and kinda thin. It sits well in a mix but on it's own it is a bit weak compared to other samplers.
The MPC 3000 to *my* ears doesn't really sound any different than the 2000/XL. It's also more of a pain in the ass to use than the 2000 or 2000XL, so I really see no point in messing with one. The 2000 and 2000 XL (and 3000) are the punchiest-sounding MPCs of the bunch, in my opinion. Very "in your face" sounding, but not in a bad way. They just knock. The 2000XL is my preferred one of those three.
The MPC 1000 and 2500 sound exactly the same. They are clean and neutral sounding -- a bit boring, IMO. The onboard effects are also pretty weak, but I guess they'd do if that all you have to work with. The thing that is great about the 1000/2500 is the ability to install a hard drive for cheap, the fact that USB and CF are standard, higher RAM capacity, and that you have the option of using JJOS, which is pretty damn sweet, even if I don't use all of the features.
Personally, I think that the Ensoniq samplers sound better than the Akais, although the Akais have much better sequencers. I've found that sequencing an Ensoniq EPS16+ rack with a MPC1000 is perfect for me because I get the advantages of both.
---------- Post added 04-18-2013 at 02:46 PM ---------- Previous post was 03-15-2013 at 10:11 PM ----------
It all depends on what kind of sound you consider "good."
The MPC 4000 has the best sampling rate specs, so if you want super-clean sounds the 4000 can't be beat. If you want that old school hip-hop sound, it's the MPC 60. If you want another classic hip-hop sound that is a bit richer and fuller, the MPC 3000 is the best. It really just depends on what you consider "best." Also, the sound of
the MPC 1000 / 2500 isn't that great. It is very bland, neutral, vanilla, whatever you want to call it. It basically just sounds like a DAW. I rarely use my MPC 1000 for sampling though... I primarily use it as a sequencer.
For what it's worth, I think that the Ensoniq EPS 16+ is the best-sounding sampler for hip-hop and other styles where you want that crunchy early 90's hip-hop sound. I think it sounds better than the S950. It also has some great-sounding effects.