I have to respectfully disagree. Back in the day, most bike racks touched the frame, but over the bike community and rack manufacturers have realized that frame mount bike racks are bad for your bike. Granted, the only place the NS really touches is the headtube, but there are a lot of racks that don't touch the frame at all...
I've mentioned it in another thread, but my buddy junked his NS after it rusted out. It also caused damage to the paint on two of our bikes. According to him, they wouldn't do anything for him. He took his NS to a scrap yard. I'm not sure if the rust was a powder coat issue that has been fixed, but their lack of service for him is what spoke to me. (only a 2 year warranty and void if you ever take off the pavement)
I"m not sure what the customer service is with other brands of shuttle racks, but I have been blown away by Kuat's customer service. Thule was also very good.
When you have racks that are just as functional (Recon, velocirax, LOLO (only touches handle bars, Alta, Yakima Hangover (only touches fork) ) I've seen threads where the NS has bikes bump off the rack on bumpy roads (mine didn't fall off, it just got scratched to hell). The NS also doesn't work with road bikes for the roadie folks. Alta is expensive, but they have a lot of cool accessories (pull out table, hammock, etc.)
I know a lot of people like the NS, but IMO, there are currently much better options for a shuttle rack. The NS is lower profile (as is the LOLO), which is a nice feature, but the frame touching trade off is not worth the risk of damage from rubbing with the NS.
I personally think that the attachment straps for the Velocirax, Alta and Recon are much better than the NS or LOLO.
I purchased a North Shore Rack 4-bike carrier in June 2014 and have found the rack to be great for hauling my Salsa Mukluk, Ibis Ripley and friends' bikes. The rack is simple to use, very versatile in the types of bikes it carries. Only problem is, it is a complete rust bucket -- it has...
www.mtbr.com
North Shore Rack Review: Rust in Bikes, Parts, and Gear
www.pinkbike.com
If I wanted a shuttle type rack, I'd probably lean towards Lolo if I wanted to get a compact rack and Alta if I wanted the best features and warranty. The 6 bike LOLO and NS are about the same price, and the NS is a bit cheaper for the 4 bike.
Alta has a lifetime warranty, which is a great selling features, has ski/snowboard adapters, bike work stand,, mobile floor stand, table, hammock, etc. Pretty cool, and a lifetime warranty. Price is high for the larger racks.