I use both, and I can honestly say, the Glyder is OK, but the SLX is really in a different league. I dont know about the new, longer ones, but the 30 foot is light, rigid, very strong and very short when closed.
The Glyder is quite light compared to the glass fibre poles, but heavy compared to the SLX. The clamps are much bigger, so the closed length is much longer than the SLX. Whats more, the actual length of the Glyder is much less than the SLX, about 5 foot less I think. They're both good poles, but the SLX is far and away a better investment, and not far off the price of the Glyder.
Hope this helps