Sorry for my tardiness.......
I'm currently having issues with my juices AND my devices lately so this may be conflicting with my results.
I've only managed to try the M601XL Atty (with 510->M601 adaptor) so far on my Protege (3.7v) and my FistPack (4.3v) with loaded carts.
I certainly enjoy the more pronounced flavour this atty offers and the fact that its a closed bridge, not an open V under the bridge like the 510 atty's. But as I mentioned, I'm having
juice DIY issues for some reason lately and my devices are acting up (not M601 related).
I hope to add to my findings as I progress with my juice problems, and have a bit more time to experiment with this new 601 stuff.
Btw, dripping with the M601XL is very good so I'm tended to think a majority of my problem is cart stuffing related.
As mentioned in another post, the M601XL (for me anyways), is not that desireable, even dripping, at higher voltages above 4v.
-Greg