Their style definitely evolved, but I like both phases equally. You've got to check out their final album, Avalon, it's a stone-cold classic, best thing in their catalog most seem to agree (and great headphone fodder). Avalon is out on an amazing SACD if you have a SACDP, a real reference recording.
Only album that's not really worth owning for me would Manifesto, but there are still 2-3 classics on there. If I were listing in order of my favorites, they'd be:
1. Avalon
2. For Your Pleasure
3. Roxy Music
4. Stranded
5. Siren
6. Flesh & Blood
7. Country Life
8. Manifesto
I've also been buying up all of Bryan ferry's solo stuff which is also out on the 1999 HDCD Ludwig remasters. You might enjoy In Your Mind (1977) and Let's Stick Together (1976) which has a few Roxy Music songs on it that he's re-done. those records are harder more thumpin' like the early Roxy stuff. His first 2 solo albums are a little kitschy kind of retro with souped up versions of older caberet style suave crooner type music.
If you try it and you do like Avalon, you should check out Ferry's solo Boys & Girls (1985) and Bete Noire (1987), they're really a continuation of Avalon sound/style and nearly as good.