The M1 increase is tighter and more invisible because it's "attached" to your knitting. The backward loop will leave a hole underneath since it's added on without being connected to anything underneath.
"Trust the pattern!"
Time flies like an arrow, but fruit flies like a banana.
Hop aboard while we follow the cloud-covered van of knitting harmony, man!! Woooo!! --Hedgehog
IngridKH on Ravelry