In my quest for the perfect journal, I tried Aquamarine (and other colors) in several journals. I'm pretty picky about feathering. Here are my results, all with a Sensa Meridian, custom ground XF nib.
Alvin Saray graph paper pad: only a very tiny bit of feathering now and then if you look really, really close
Apica CD-5 notebook: similar to Alvin Saray
cheap copy paper (Hammermill Great White 20#, 92 brightness, 30% recycled): moderate feathering, some line widening
Clairefontaine wire-bound notebook: negligible feathering, maybe can see a bit every few lines
Derwent journal: tiny bit of feathering
Exacompta Journey notebook: negligible feathering
Exacompta Nostalgie refill: teensy tiny bit of feathering, less than Alvin Saray
hand*book journal: similar to Alvin Saray
Markings by C.R. Gibson 4x6 journal: moderate feathering
Miquelrius flexible notebook: a lot of line widening, some feathering
onion skin paper (white & buff): no feathering!
Pen + Ink journal: tiny bit of feathering
Rhodia: negligible feathering
If my scanner was working, I'd post pictures (well, that and I'd have to find some place free to host the pics

). Hopefully I'll get the chance to do so before school starts up again!