The ESP Guitar Company

Actual EMGs are good quality and sound good and of course more expensive, lower end guitars have crappier and cheaper pickups and yeah different combinations are made for tone reasons, but EMGs and the cheapr LH arent and cant be mixed

the ESP LH-300s aren't total crap, imo. i think they are supposed to be the equivalent of the EMG HZ-H4s, but i think it doesn't have the trademark quik-connect system.

Actual EMG pickups are indeed much better though. if you've played dual EMG 81s and you're comparing it to LH-300s, well...the answer is obvious.

Actual EMGs?

i think he means if the sound is differnt if the same pickup is used in the bridge/neck, when switching between each other. (either the 81 or the LH)

yes, the sound is different, even if the same pickup model is used in both positions.

the sound changes according to the position of the pickup under the strings.
a pickup closer to the bridge sounds brighter, sharper;
the one closer to the neck, warmer.

on a 22 frets guitar, the neck pickup is under the second octave (24th fret) and the sound will be different (warmer, fuller) compared to one with 24 frets.
(even with the same pickup model, same wood, same guitar model)

when selecting both pickups you get a mixture of the sounds (both at the same time).

Pickups in the neck position will also be louder, as the string has more room to vibrate in that area, which is why you tend to find that bridge pickups have a higher output than neck pickups. Not sure how noticeable this is with EMG's though, since loads of people use the dual 81 combo.