Alegreya seems like a Garamond derivative, but it has a very interesting character; the glyph stroke widths—especially the verticals—have an intriguing taper. I really like the lowercase italic 'g' and 'h'.
Playfair is Didone, and I feel Didones (this includes TeX's default, Computer Modern) don't really do well on displays because of the very high contrast between the ball serifs and rather thin vertical strokes. Otherwise it's a nice Didone: I'd use it, but as a printed typeface.
I'm not the biggest fan of Ubuntu. Especially the lowercase 'r', it's got a weird shape.
Playfair is Didone, and I feel Didones (this includes TeX's default, Computer Modern) don't really do well on displays because of the very high contrast between the ball serifs and rather thin vertical strokes. Otherwise it's a nice Didone: I'd use it, but as a printed typeface.
I'm not the biggest fan of Ubuntu. Especially the lowercase 'r', it's got a weird shape.