I have been using colemak for the past 9 months and I am not close to my original speed at all. To be exact I am 20% slower now than I was at my peak just before I switched. My highest speed so far has been 370cpm (74 wpm) with my top speed being 480cpm (96 wpm).
The problem is finger confusion. The homerow is so dense with colemak that I am constantly adding extra characters or jumbling the order when I come across close key combinations. I am also switching S and T alot and also I and O and U alot.
What do I do to correct this? One great thing is that all pain in my wrist and fingers are completely gone but maybe that is because I am typing at a slower pace.