_tim: I believe Liege and bGates were meaning that instead of backsquatting with a Smith you can always clean and then front squat instead (I could be wrong though).
Firm, I think your reasons for using a Smith are good ones and at the end of the day it's a personal choice. Just as some folks squat with bad form so they could use bad form in a Smith. Both could lead to problems. Experience really helps. If I had to use a Smith I'm pretty sure I could use it safely but I would always start out with a light weight until I found the groove.
Here's a comment from Blade quoted from
this thread:
<div></div><div id="QUOTEHEAD">QUOTE</div><div id="QUOTE">One of the main arguments against Smith squats were that the hamstrings would be recruited less, hence the stability of the knee joint would be compromised. I read a study where just this premise was tested, and the hamstrings showed about equal recruitment between Smith vs. regular squats.
Foot placement is important, so just experiment until you find the better 'groove' for the movement. On my last cycle I did another horrific no-no on squats (regular), I used a wedged block of wood to elevate my heels which enabled me to go deeper without leaning excessively forward. </div>
It seems that Blade only switched to Smith machine squats because he was having problems with regular squats. This was also way back in 2003 so perhaps there has been more research done since then?
When I tried Smith squats I just hated the feel of the restricted line of motion. I hated it for bench too, but I quite liked it for shoulder press. Personal biomechanics do really seem to make a difference but I can't help feeling that, for the majority of lifters, learning to exercise with free-weights (allowing for a more natural movement) has to be a good place to start.