the mic-in is much better on the R09-HR than on the LS-10. The line-in on the LS-10 requires a very hot signal too
The issue with the LS-10 mic in isn't noise, but bass roll-off. Even with the low-cut switch off, there's still a roll-off... but if you have bass-heavy mics like my SP-TFB-2s, this isn't really a problem in my experience. It would be a problem with a lot of the small cardioids or hypers, though.
With line-in, though, you definitely need a hot signal - and even then you need to crank the input level to 10 for unity gain. My E-MU 0404 USB in analog monitor mode can drive it without problems (set output level to about 6.5), but when I plugged the LS-10 into my stereo's tape out to transfer some vinyl to digital, the stereo didn't really have enough oomph - at least the input is clean enough that the transfer could be boosted in post after recording in 24 bits.