My friend was recording and he starts his recording using his LTD EC 1000, but then he has bought an ESP Eclipse ll and continue the recording with that guitar. He was like you saying: "is the same there are not big difference and bla bla bla", but when he keep attention to the first recordings with the LTD and the second one with the ESP, even using EMGs, he told me that there are a big difference in the sound. The ESP has more definition and balance, while the LTD was more treble oriented. He re-record the previous songs with his new axe!.
Sometimes a cheap guitar and an expensive one does not have a huge difference under the eye, but cheap guitars are pure cosmetic (I have had very bad experiences after sanding some of them), and the expensive ones uses better materials, and that is what you are paying!.