I have owned handguns before but never any rifles.  I am looking at the Modern Materiel SBF and Patrol.  Is one "better" than the other?  What is the reason for wanting or not wanting the shorter length?  Are there better options out there for a first rifle purchase?

SBF is a NON-NFA "Other". The Patrol is a rifle. 

In my opinion, the Patrol is a nice rifle but expensive. You can spend less and have a similar rifle that goes boom. S&W and Ruger make rifles for about $600 (and in NJ compliant form) that will function as well and allow you to spend more money on ammo and range time. As they are AR platform, you can change parts as you like.

 

The SBF is another animal as an NON-NFA Other. That's the going price for an assembled "other". They will go bang just as well as a rifle. The concerns here are around the NJSP have currently ok'd them as legal in NJ because they are not pistols, rifles or shotguns, but in general LEO's may not be versed in this. So in the event you are stopped traveling with one the LEO's will see a adjustable stock, non-pinned muzzle. It's a crapshoot if this will be an issue or not. Some people carry lots of documentation in the hopes this diffuses any issues.  

I agree with Clifton.  Start with a standard rifle from a reputable manufacturer, something in the mid-range price but of course whatever is in your budget.  There are great options for every price range.  ModMat Patrol is a fine firearm.

I have found these guys to be helpful to me:  

https://www.pewpewtactical.com/ar-15-definitive-resource/

https://www.pewpewtactical.com/best-ar-15/#toc11