I have been getting restylane, Collagen (before Restylane came out), and botox injectables for almost 10 years now.
Skilled MDs need to perform the injection for it to work well obviously, but I have had great luck with a few different doctors as the ones that I trust. Do your research, and don't go just go because a doctor has a "deal". Its important to know your doctor and get referrals from other folks that have had the same treatment.
Over time, there have been a couple of bruises along the way, but thats part of the deal when you are getting these treatments. Any great doctor can cause a bruise and that doesn't mean that they did a bad job....it just means that you incurred bruising which eventually goes away.