The chains on this lock are 9mm in diameter, which makes it good for only quick stops in busy urban areas. Chains under 13mm can still be cut with bolt cutters, which isn't good enough for higher-risk settings.
The Bordo 6000 can be wrapped around a wide variety of objects, since the shape is relatively malleable. U-locks have a rigid 'u' shape, which you cannot bend to suit the object you're trying to lock on to.
This folding lock is a great alternative to u-locks and chain locks of the same security category. If your security risk is medium or low, for example, you have a cheap bike, or you only ever leave it in the hall of your apartment building, the Bordo 6000 will do the job.
As the name suggests, the folding lock folds into a compact bundle, which you can just attach to your bike using the holder it comes with. It's lighter than chain locks, so you won't be carrying as much extra weight with you.
This Albus u-lock is a great option if you have an expensive bike, and if you need to leave it in more dangerous areas of the city. The 'u' part o the lock is a parabolic shape instead of round, which makes cutting it with bolt cutters, car jack or saws too time-consuming to be possible. Every part of this lock is made from temper hardened steel. Any thieves would need power tools to break this lock.
This lock weighs around 4 lbs, which is not the heaviest nor the lightest lock. Considering the security level, it's definitely one of the more lightweight options when compared to locks with a similar security rating.
U-locks don't generally transport well outside of backpacks or specialized u-lock holders that mount to the frame of your bike. It's a choice between having less space and more weight in your backpack or cluttering up your bike frame with an extra accesory.
The New York Noose has a Sold Secure rating of Gold. The chain links are 12mm thick, and are six sided instead of round, which makes them impossible to cut with manual bolt cutters. Given that any thieves would need to use power tools to break this chain, it will buy you plenty of time to save your bike, and it will also deter most thieves from stealing your bike.
The New York Noose gets its name from the cinch loop- you can wrap the chain around your object of choice like a noose. This allows for nearly the same usable length as a standard chain lock, but without the actual extra chain links, which means less bulk for you to carry.
There is an included cable with the U Lock, that allows you to secure the other bike wheel (not locked with the U Lock itself), or the seat. This is great for city riders who have quick release wheels, as an unlocked wheel makes for easy theft.
Do not expect this lock to protect your bike in high risk situations (leaving your bike where there's a crowd, especially if your bike attracts thieves attention). The tubes 13mm diameter is not invincible against bolt cutters.
The New York Legend 1515 chain is very heavy (15+lb). It's so heavy that it would be impractical to take it with you on a daily basis, but it's great to be used as a stationary lock at, for example, home or work.
With a chain thickness of 15mm it's impossible to damage this lock with manual bolt cutters. If the thief is really determined, they'd have to use power tools, and it's hard not to notice someone sawing away, sparks flying at a bike chain. At the very least, this lock will buy you plenty of time, or attract lots of attention to the thief brave enough to attempt to break it.