I have had a blast fishing switch rods from 4wt on trout to 8wt for steelhead. I've cast rods from TFO, Echo, Orvis and Sage and have friends with rods from Redington, Beulah, Meiser and Rainshadow. They can be great tools if you get the right one for your needs and get comfortable delivering it in the method you prefer. If you do a search on the site for SWITCH you'll find a lot of previous discussions. Knowing how the rods are rated by their manufacturers (on single handed scales or two handed scales) will help. Knowing the grain windows for the rods will help you find the best lines. Here is a thread I recently added with some information that I have collected while playing with switch rods.
http://www.washingtonflyfishing.com...-Some-Switch-Rod-Information?highlight=switch
http://www.washingtonflyfishing.com...-Some-Switch-Rod-Information?highlight=switch