Soliciting expert opinion: which sans serif is the better companion for Gentium? Alegreya Sans or Linux Bioline? To me, Alegreya Sans is much more similar in style (sharp angles where bowls/shoulders connect ot the stem; shape of the y tail, large x-height, rounded spurs of a,u,d..., even more similar cursives), but it is less readable and not so orderly and clean-looking. Linux Bioline is very clear and readable, but a slightly different cup of tea, so I am not sure if the two do not clash. (And yes, I do know about Alegreya serif to go wit Alegreya sans, but I have to use Gentium (and morover, Alegreya has some glitches...)) Please see the attached PDFs.

Many thanks for any feedback!

Lukas

linux_biolinum.pdf alegreya.pdf

In the specific setting presented, I think Biolinum works better. But, given its noticeable inscriptional qualities, it would also depend on the subject matter of the text.

In general, a contrast in style when pairing a serif with a sans can be intentional and welcome, when they interact on a hierarchical level.

In that regard, I would experiment using the sans also for headings and drop caps.

Many thanks for your input! LB was indeed my first choice (the subject matter is serious Roman Catholic theology, so "inscriptionality" is welcome, I suppose). I agree about the contrast in general, I just was not sure if it isn't stuch half-way, so to speak: not enough different and not enough similar. 

I have already experimented with LB for drop caps (indeed, its style calls for such a usage), but haven't been convinced. But I will give it one more try; Gentium indeed doesn't seem to work very well in large size. As for headings, I will consider that, too, although I am afraid there is too little "hierarchic space" between title(s) and headings to make them all sufficiently distincs using the same font...

One last note: you could want to substitute Linux Biolinum with Libertinus Sans.