I recently purchased a Jake Locker Titans jersey, the new Nike one. I noticed a lot of differences when wearing it so those who wear or even collect jerseys but may not know the differences between these new Nike jerseys and the old Reebok jerseys, I'll give my 2 cents worth on it.
Note: This is just a comparison of the plain "Replica" type jerseys
The sleeves of the Nike jerseys are not the silky, loose-ish material from the Reebok jerseys. They are of a different material that is stretchier and tighter. The logo is smaller on the sleeve of the Nike jerseys, while the Reebok ones carried a larger logo. Another obvious difference is the Nike Logo on the sleeve rather than the Reebok Logo (this sentence was brought to you by Captain Obvious).
Note: Click on the photo to view it in a larger format. You can see some of the things I am talking about better if you do that.
Collar/Tag/Immediate area below Collar:
The collar is a lot different on the Nike jerseys. Reebok jerseys have a large, loose collar. On the Nike jerseys, the collar is much thinner and tighter, and also carries both shades of blue. The NFL logo on the Nike jerseys only shows the NFL Shield, while the Reeboks have the NFL Shield but above it the word "Equipment". The Nike NFL Shield logo also has a plastic-like feel, whereas the Reebok felt like a threaded material.
The Tag on the Nike jerseys are screen printed on, rather than the loose hanging tags from the Reebok jerseys, providing more comfort for your neck.
The area below the collar basically is the same, containing the word "Titans", only the word looks smaller on the Nike than on the Reebok. The front is of a different material than the Reebok, again being of a stretchy and tighter, more comfortable feel. (below is a comparison of the Nike to a Reebok)
The numbers on the shoulders are about the same size.
The numbers on the front and back of the Nike are smaller than the Reebok. If both are screenprinted replicas, the Nike has a nice smooth feel that (in my opinion) will hold up much better than the Reebok screenprinted jerseys (I have had Reebok jerseys where the screenprint fades over time).
The bottom of the front side:
Basically here you can see the new Nike tag and how only up the side of the jersey is the mesh-material that the entire body of the Reebok jerseys are made of.
The Nike jerseys only show Navy blue on the collar and parts of the sleeve, whereas the Reebok jerseys would show Navy from above the nameplate to the entire collar area.
The nameplate is around the same area on both jerseys.
The Nike backsides are still of the stretchy tighter material.
Side by Side view:
You can see how loose the Reebok (left side Britt jersey) is, compared to the Nike jersey that is not near as loose.
Reebok jerseys will definitely be on the cheap now. This Nike jersey cost $100. Most replica Reebok's were about $60 to $80, but you can bet that price will be slashed now.
My final analysis:
Pros to Nike: Much tighter and fits a lot better. Way more comfortable than the Reebok. Screenprinted numbers and nameplate will probably hold up very well over time. No hanging tags make for tremendous neck comfort. I love the material rather than having the whole jersey being mesh. Look wise, I like Nike much better than Reebok.
Cons to Nike: Going to be very expensive to invest in these if you are a collector such as myself. The sleeves and shoulders don't really hang and flow with you like the Reebok jersey sleeves/shoulders, but it's only when you sit down and move your arms forward (like if you sit back in a seat and put your elbows on a table you'll notice it's a little tight).
Pros to Reebok: Going to be cheap to get. Fits comfortably even if it is loose. If you like loose clothing rather than having something contour to your body, then you will like the Reeboks better.
Cons to Reebok: The player universe for Reeboks has probably stopped growing, so if you were to want a Kendall Wright Titans Reebok jersey, you probably won't be able to get one unless you get a custom one (which costs more than regular and if it's screenprinted then it ends up being uncomfortable and itchy to wear, trust me). Reeboks are too loose for my liking, and comparing the all-mesh to part-mesh, I prefer the Nike part-mesh.
Ultimately it's up to you. I really am impressed with the Nike jerseys. They are super comfortable and honestly I think they're worth the investment. If you're a cheap person (nothing wrong with that), you'll probably want to stick with Reebok for as long as you can!