Another thing, so i got my pair of Line Audio om-1's because i want to come as close as i can to reproduce as my ears heard it, so the more neutral the mic the closer it gets to our hearing.
I've always wanted to try Line Audio mics for stereo recording - they seem like great value!
However they may not be ideal for measuring due to their small/short bodies which would like result in undesired reflections causing ripples in the measured high-frequency response.
Also, unlike dedicated measurement microphones they do not come with individual calibration curves. These are especially relevant for situations where you measure with the microphone pointed to the ceiling (common in acoustic measurements), as off-axis microphone response always exhibits some HF roll-off, even for flat on-axis response mics, e.g.:
You can see this trend in the Omni1 polar plot on the line-audio web as well.
But these measurement mic's are they not even more neutral? How good are they for recording music etc.?
Self-noise of measurement microphones, especially cheap ones, can be relatively high and therefore less-then-ideal for recording purposes. Also, they are all omnidirectional which is not ideal for some recording situations. Lastly, many people like certain types of frequency response coloration on recording mics.
But indeed they can in principle be used for recording, just as you would use any other omni mic.
I'd just suggest to look at measurement microphones that are provided with calibration curves for 0 and 90 degrees and are either known for being consistent between units or are calibrated by some third party.
E.g. I ordered my calibrated Dayton EMM-6 from cross-spectrum labs (they are in USA), but it seems that
hifi-selbstbau.de provide a similar service in EU.
Good luck!