Am I alone in thinking focus 3 is their best album

Certainly is a great album, with great melodies and compositions. I guess is a matter of personal taste, but if you think it's their best, you certainly have good taste.

I agree, a phenomenal album that doesn't get enough attention!!  I'll listen to it today, thanks!

It's my favourite of theirs

It is certainly one of their best, but I think Moving Waves tops it. 

Yes, it is their best. I like its improvised feeling. It feels live, as though I could imagine reaching in my pocket and pulling out a ticket as I listen. I like all Focus albums, but I agree 3 is the best. I like that it's long. Hamburger Concerto, as delightful as it is, always seems to short to me.

You are definitely not alone.

I don't tend to think in terms of best, but Focus 3 has been my favourite Focus album at one time or another. It has rather depended on the day and mood, sometimes I would rather listen to the jazzy Focus three, sometimes the "Meaty masterpiece" that is Hamburger Concerto, sometimes Moving Waves. Ultimately, I don't think there is a best as I think different albums have different things to offer.

I haven't listen to Focus much over the past decade, but it was one of my absolute favourite bands.

Focus 3 does have the highest Focus studio album rating at rateyourmusic,see https://rateyourmusic.com/artist/focus , but at PA it has a lower rating than Hamburger Concerto (the highest rated) and Moving Waves.

Here are two reviews from rateyourmusic:

dempsey wrote: hadn't listened to this music in years and now I'm wondering why I've passed over it so many times. The is simply the best album from Focus. They really came into form with 3or III (depends on if you're reading the front or back cover). From the gorgeous simplicity of "Love Remembered" to the extended jam of "Anonymous Two" Focus covers most of the bases of prog music. Some jazz, some classical, some rock... and all delivered with a pompous flair and the chops that make it all work.   If you only want one Focus album get 3.

jazzis wrote: This is the 3rd album by the great Dutch group Focus, led by flautist / keyboardist / composer Thijs van Leer, which also included the brilliant guitarist / composer Jan Akkerman. Following the somewhat unfocused debut album, this masterpiece finds them at their absolute best, an album which is one of the best classic Prog albums of all times and an essential piece of music history. Originally a double LP it includes the suite "Anonymous Two" (over 26 minutes long) is a beautiful example of the scope and imagination of music made at the time. A timeless classic!

Let's just say that this double studio album would've stronger being reduced to a single disc affair or a three-sided one (live Johnny Winter's Second Winter was), like many double album, such as Tommy, White Album, The Wall, the Lamb, Works Vol 1, etc...

My second favourite, behind...