I had much the same experience. After finishing the ultimate collection, I cracked open my Companion for the summary of 1-100 and started a re-read at 100. I'm up to 123 and it's just such a fun read. I know the holes in my collection start around the 210 where I originally started losing interest in the series, but now I'm trying to track those missing issues down and get caught up.
Maybe I didn't give Malcom a fair shake the first time through? I'm looking forward to finding out.
I probably should have just re-read the whole run, but I'm hoping for subsequent volumes of the Ultimate to follow sooner rather than later. I too would have preferred the Compendium style (in color), but the Ultimate format really brings out the art.