Okay, first off, remember we all "practice" dentistry so it is an always evolving learning curve, and with experience (for most folks atleast) does come greater wisdom! 😉
Now, is a freshly graduated dentist out of school competent? For the most part that answer is yes. Obviously some folks just don't get it, but if you're doing well in school, and find treatment planning and sequencing of treatment not very difficult, then you shouldn't have a problem. There are however some folks who graduated school who aren't competant(then again some folks who have finished a residency, and some folks who have been in private practice for a while also fit into this statement ). 😱
Freshly out of school, speed will come to most very quickly(it's amazing how fast you can do things when you don't have to check with preceptors every step of the way). For most folks within a month or 2 you're having that handpiece move at full throttle. The most difficult thing that I've found(and I'm still finding this true after over 3 years in private practice)is the practice management side. Find a reputable accountant who you trust early on for some prudent tax advice and that will help alot!
For the practicing in the NYC area, don't worry about it. As someone who practices almost equi- distant from NYC and Boston, as I was looking for practices I would see adds for both cities, and frankly there are alot of them. Remember alot of folks will want to work around a city, and based on the demographics of practicing dentists as a whole, there are more dentists retiring every year than graduate by a substantial margin. If you are looking at going into ppractice with another established dentist, then strongly consider a residency first. Here's why, first off the residency will allow you to get upto speed before you hit private practice. Most residencies will also expose you to trying to manage not only the patients in your chair, but also those in a hygienists chair at the same time. Most residencies will also expose you to alot more "extreme" cases than you'll see in private practice, so you'll be better able to handle the emergency patients in private practice. Here's the most important reason though to consider a residency if you're thinking about going in with someone, all those adds that say "GPR/AEGD or 2yrs experience required" Most of those practices are the "better" practices that alot of us are interested in. Consider a residency, I know that I'm totally biased towards this point of view, but thats how much of a positive experience my 2 years in my GPR were! 😀