Given that the difference in focal length between the 28 and the 35 doesn't matter,
I think in most situation you will be more satisfied by the 28.
It is better build, has the faster AF (also certainly the more silent one), it usually
produces slightly better contrast. .... except if straylight or contralight hits the lens
in that case, the 28 will lose contrast very soon, while the 35 remains usable quite
well.
It's a great little lens. IMO, for real life use it outperforms the 85 F/1.8 quite easily. Usable at F/1.8, very good at F/2. I used it and a 50 F/1.8 Mk I plus 85 F/1.8 as a cheap low light trio, which I all replaced with time with their L "equivalents" (85 first... <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt=':lol:' />). However, when I got the 24L, I felt it was a shame to sell the 28, because it was that good. I only did in the end, 9 months or so later, because it just didn't get any camera time anymore. Fortunately, I found a very good home for it, and if need be, I can still borrow it <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='

' />.
Lovely lens, much underrated.
Kind regards, Wim
Gear: Canon EOS R with 3 primes and 2 zooms, 4 EF-R adapters, Canon EOS 5 (analog), 9 Canon EF primes, a lone Canon EF zoom, 2 extenders, 2 converters, tubes; Olympus OM-D 1 Mk II & Pen F with 12 primes, 6 zooms, and 3 Metabones EF-MFT adapters ....