I carried an SC340 in a Desantis Apache ankle rig for a few months.
Pros:
• Easy to conceal as long as I wore boot cut jeans.
• Serviceable solution for a job where I was spending most of my time sitting. This is less true if you're obese or have mobility issues.
• Comfort and walking fine were not issues for me.
Cons:
• Slow draw.
• Depending on your setup, you may need to take your eyes off the target to draw in order to clear a pants cuff.
• If discretion is important, you have to be conscious about things like crawling under a desk to plug something in.
• I reconsidered my tactics when I ankle carried. Faced with a threat while carrying on the belt, I would generally seek cover / return fire. Faced with a threat while ankle carrying, I would generally seek cover, draw, and assess.