The 34 is a great gun, but is better for IDPA or USPSA or other shooting competitions.
The 17 is better for GSSF because you can use it in more divisions.
I have both, in GSSF I use the 17 in Am Civ and Competition... just so I'm shooting the same gun twice, and in my mind that gives me more time with that gun and hopefully better scores. Trying to shoot two *different* guns is a little tougher, at least IMO.
Ron M. ('59 is my birth year)