The 2014 TCS NYC Marathon was my first NYC Marathon, and it was amazing.
From start to finish, it was an experience I will never forget.
The expo was great- it get a little crowded, but I didn't have to wait to pickup my bib and shirt. There are TONS of booths, and many give out free samples, plus you can pick up just about anything running related.
I opted to take the option of the bus from the public library straight to Staten Island, and from what I've heard that was definitely the way to go. You wait on one line and get right on a bus that delivers you to the start. You do wind up waiting a few hours though, so I suggest find a spot and camp out. Wear tons of layers to keep warm and maybe bring something to eat, read, listen to.
Once your section lines up though, then it's non stop. You will walk slowly to the start and once you cross the start, it's on. Staten Island goes by quickly. You're on the bridge a lot longer than you think, but it makes for great photo ops. Brooklyn has TONS of spirit and everyone comes out to cheer you on. Queens is great, but you're not by people for a lot of the borough- be weary of the 59th street bridge. It's more daunting than it appears. You're in Manhattan and then the Bronx for a very short while. Then you go back into Manhattan to the finish.
There are tons of photographers, and their aid stations are at every mile after 3. When you finish you get your medal, and photograph taken. Then you get a bag of snacks, a foil to keep warm, and a really nice poncho.
It's a class act from start to finish, and NYRR really makes sure its an experience you will never forget.

This is one of the best races out there in my opinion. I've done this race in 2010, 2011, and 2014. In 2010 I was a newbie runner, and this was only my third half marathon, and honestly it did not matter. There are people of various running abilities that participate in this race, and everyone is really there to have fun.
The runners consist of primarily females, and I think it's a very good example of women supporting each other to the finish. Everyone is very friendly.
The expo is pretty good- in my opinion it was a little better in the earlier years, but there are seldom any lines to pick up your bib and tee. You also get a nice drawstring bag. The parking lot can sometimes be crowded, so I might recommend someone dropping you off and waiting outside so you can run in and get everything.
Race day can be a little hairy if you don't leave early. There is always a huge line on the highway to get into the parking area so you definitely need to leave early. Once inside I've never had any issue finding a parking spot.
Everyone dresses up, which is really fun. The race does go off on time without fail. The course is pretty flat with the exception of 2 or 3 hills. It's on the street, too- so sometimes the pounding can be a little tough on your calves.
You run through the streets of Long Island and pass by both residential and business areas. The mile markers and water/gatorade stations are set up consistently at each mile on the course. At mile 12 you receive a feather boa and tiara. Then once you finish a shirtless fireman presents you with your medal, and you receive a glass of champagne. There are also post race snacks to help you refuel and entertainment.
With the cost of races increasing all of the time, it's nice that with this one you feel like you're definitely getting the most for your dollar. It's not only a race, but it's an experience.
I think this is one of the best half marathons out there.

I participated in the NYRR 5th Ave mile in 2014. It was a great experience! Since it was right before the marathon, it was nice to keep how all of my training was paying off on a very flat course straight down 5th avenue. The heats go off by gender and age group, so it's structured a bit differently than most NYRR races, but they are great at making sure everything goes off on time. You get a nice t-shirt when you pick up your bib, too.
It's a lot of open space, so you're able to sprint for a mile and not really bump into anyone, and once you finish they have water waiting.
I think it's a lot of fun.

I completed the NYC Half in 2013 and it was a great experience! I thought it was going to be the same as the NYC marathon, but it's completely different! The expo is great- it can be a little crowded, but there was a good amount of booths. I received a tee and bib there. The marathon course is fantastic- it takes you through NYC and even right through Times Square. There are a lot of photographers so you wind up with really great shots. Even for being on NYC streets, the course is not congested at all. There are aid stations at just about every mile and the volunteers are great at handing you water.
The course ends all the way downtown so definitely have someone pick you up and park a few blocks away from the finish. It's NYC though, so I really didn't expect it not to be crowded downtown. You get a really great medal at the end and refreshments. You also get wrapped up in the foil to keep warm, so they really thought of everything.
I think it's a race that lives up to its hype.

I completed the NYRR Bronx 10 Miler in 2012. It's a nice, straight, and relatively flat course. I think it's great if you're looking for a good longer run for training. You're primarily running down what is normally a high traffic area, so you pass stores and houses primarily. The aid stations are at every mile and the volunteers are ready to hand you water/gatorade. When you pick up your bib you get a nice tee, and once you finish you get a really great looking medal.