I am responding to your post to give my two cents worth. I read the original post because I, too am upgrading from a D5500 to a D750. But in reading the thread, I realized that there are a lot of misconceptions as to picture quality between the two formats. A FF camera will not necessarily result in better picture quality. You need to understand the differences between the two sensor sizes and determine what these differences mean to the type of shooting you do.

First, an APSC format will give excellent results, and for many of us (myself included), this format could be the only camera we will ever need. I have been using a D5500 for two years and I have gotten some great shots. My not so great shots have to do with operator error and learning the art of composition (Nothing to do with the camera). I have some of my better shots hanging on my wall, which is my goal on every shot I take. So far, all of my wall worthy shots are printed 8X10, but I know they would look just as good if they were printed larger. My point here is that these shots would be no better if I used a FF camera.

So why would I want to move to a FF and what are the differences? For starters, one could print in larger sizes with FF. This doesn't really pertain to me (More so for a professional), but it would allow one to crop and still get a decent size print made. The most significant difference is that the larger sensor of FF and larger pixel size results in gathering more light in low light situations, and thereby resulting in less noise when using higher iso's. In my case, I want to do night sky shooting, so I will benefit from a larger sensor. Now, I don't need a FF sensor to get great night sky shots, as evidenced by a recent post of a night sky shot using a D5100. But, me being a technical geek, I think I can benefit in the long run, as I like to do mainly landscapes, especially in low light. Which brings me to another reason for moving to FF, which is that you can get a wider angle of view. I have a 20mm f/1.8 that I use for landscapes and night sky. On the D5500 this an equivalent focal length of 30mm. I have been in situations where I could have used the extra 10 mm to get the composition I wanted. Again, I don't really need a FF; I just need to use my imagination and creativity to still get a good shot.

Another thing I noticed in reading through this thread is that someone is using the DXO mark scores to judge picture quality. Big mistake! You really should fully understand what the scores mean before you make judgments on buying a camera. I won't elaborate because I don't want to steal this thread, so I will start a new one on this topic.

To summarize, I would like to say that picture quality is a relative term, and one should understand what factors affect picture quality, and how they will affect you based on the type of shooting you do. Sorry to be so long winded, but I just had to say it.

I went to the D610 (from D3300, which I kept, and a D3400 which I bought as a backup), mainly because I could afford it, the kit included a telephoto, and I simply wanted to have a full frame digital. I've been very happy with the D610, although I don't use it exclusively. I tend to take LOTS of images, download them to external hard drives, back them up on external hard drives, and mess with them using Photoshop. So additional features such as WiFi connectivity are not really important to me. I have a Sigma 150-600 telephoto and a Sigma 2X converter and those both work well with all my Nikon cameras. The D610 has a port for a wire remote (as does the D3300 but not the D3400), and that wire remote can be a really nice item. The D610 also has a USB port that accepts the same wire as my Canons (don't know the technical name of that shape), and two SD card slots. So I'm very happy with it. I've not used the video on the D610, but the videos on those other Nikons are excellent, at least for my use. Hope this helps.

Charliesmom, Your brick and mortar may be able to give you a discount, comparable to NY, they all have expenses. I supported our local camera shop for 30 years until the day they abruptly shuttered with no warning to anyone. Store loyalty sometimes is an advantage, until the doors close. As long as the store is an authorized NikonUSA you should never have to worry about the body getting serviced by NikonUSA, and always choose the national service center; they put a 6 month warranty on the entire camera no matter what is repaired, replaced.

I found that sometimes I was ahead by talking to Nikon directly, then shipping it directly to Nikon LA/NY once they approved sending it in, without involving the dealer whichever half of the country you're in. Our dealer was always busy and it sometimes wasn't as clear to him that when Nikon said 'send it in' that didn't meant 5 days from now. If, it ever needs service, since if you buy locally you're supporting him, be sure to ask that he include free handling and express shipping to Nikon repair. The last time ours was in LA, they rebuilt it in 4 days from the time they got it into the que; I always pay for overnight return UPS rather than have one bump along over the Rockies for a week. Just in case, never assume if you need service that either the dealer or Nikon knows you want to pay for full catastrophic loss/damage replacement value for shipping insurance. It doesn't happen often, but one woman's camera had just been serviced at the Nikon facility, UPS fetched it and the same day the UPS truck was totaled, her newly refurbished camera was in pieces. The token $100 UPS check was all she had to show for it. When you pay for the best, don't ever cheap out on shipping or insurance. Happy shooting, sv