Carbon Fibre has a much, much, much lower thermal expansion value - its like 0.2 vs 10.0 for aluminium or steel. So if you are long exposure imaging expect to get temperature variances which will mostly like shrink your telescope tube enough to impact your focusing (unless you're using a robofocuser or something). Otherwise every so often 20 - 30 minutes you might have to re-adjust focus.
Carbon Fibre is far less likely to be affected by a significant tempeature change from start of night to end of night, so your image should stay much sharper with fewer adjustments over the course of your imaging.
So for shorter imaging < 20 minutes, fewer worries, for longer imaging, more focal adjustments required or an auto-focusered needed more to adjust to tube length changes.
PS
Lee just dropped his surplus CG5 to about $1,100 ... tempting! <TABLE class=content cellSpacing=0 cellPadding=2 border=1><TBODY><TR class=tbl_text><TD class=desc>Celestron CG5 Go-To computerised mount with s/s tripod, new</TD><TD class=price>$1099.00</TD></TR></TBODY></TABLE>