FF5 if you want to listen to music naturally and beautifully, DX7 if you want to listen to music in a fun way, FF5 if you want to listen to footsteps in games, the fit is on the same level, and if you use DX7 with a spare filter, it's close to FF5, so if you don't have a lot of budget, DX7 is great. Good
Sorry, I don't have FF3. However, when using the blue filter, the sound was similar to FF5, so I think it is a monitor sound. FF3 may have stronger bass because it has a beautiful open sound.
In terms of sound quality, the localization is good and the sense of separation is good, but... it's a shame that the selling vibration unit gets in the way.