I'm very very new to USPSA as I've only shot 2 matches in the fall/winter of 2009, but I'm hooked no doubt about it. My perspective as a brand new newbie to the sport might help answer this question you've posed.
I was introduced to the sport by a friend who really took me under his wing. He took me out to the range and introduced me to the types of targets and had me shoot and learn about the basics before I attended a match. I ended up just watching one match to see what it was all about, which afterwards made me very impatient for the next match to arrive Had it not been for his persistence and time I probably wouldn't have had the "guts" to attend a match in the first place. The idea of competition shooting to someone who has never done it before is very intimidating. Going out to the range ahead of time and learning about the sport really helped me during my first match. I wasn't intimadated by the language or rules, and I had a general idea of what I'd be shooting at (except that damn texas star which screwed me over big time).
I've had the nicest guys in my squad both times. They have looked after me and given me invaluable constructive critcism and advice. I've been offered ammo to shoot, and even guns & equipment to use should I need it. That type of generousity touches the heart and not only takes away the worry about "competition" but adds a feeling of comraderie and family to the event. My friend has told me, and I believe it, that USPSA is the only sport he knows of where someone could come to a match with nothing on them, and his squadmates would find him all the equipment he needed to shoot his first match. I am looking forward to next month not only to shoot but also to spend time with the fellows I've met.
The first 3 shoots are free to new shooters at the local club which absolutely helped get me hooked. Ammo is expensive and removing that added cost in the beginning removes one more excuse I could use for why I couldn't go that Sunday. After 3 matches I think anyone would know whether they were hooked or not. I was hooked after one It has also helped me that I have two good friends who have offered to help me reload with their equipment while I am short on funds but full of excitement. If I didn't have their support, the sport might be cost prohibitive for me. I know that the veterans can't take every young shooter under their wings, but it made the difference for me. I've gained a fun once a month activity, along with some new friends that I've been able to meet up with outside of the matches. I know that when I'm older and able, I will be on doing the same for someone else who is in my position now.