I had a u-lock and some theives made short order of it with a disc-grinder (I caught them just as they had finished cutting it and they simpley walked away. Freagin bolt was still hot when I touched it.)
So i bought a thick chain on Amazon and havenn't had a problem yet. U-Bolts arent great because they don't move around, making them easier to cut. This is the chain.
If you have to do it around a steel pillar. Then pair it with a chain that is of equivalent strength. https://www.amazon.com/Schlage-12mm-Noose-Security-Chain/dp/B00X6E0NO0/
Of course if you can you have a secondary lock and you leave the chain there. Because carrying around 7 pounds of chain is not ideal.
A beater bike is the way to go. I've found old 3 speed raleigh or ccm bikes attract little attention from opportunistic thieves. A shiny new bike of any kind will be a magnet for those types of people.
The more dedicated bike thieves that use angle grinders and bottle jacks probably won't waste time on an old 3 speed with rusty fenders and a bent wald basket on the front. U-locks can be pried open with a scaffold pipe so I use a (chain like this)[https://www.amazon.ca/Schlage-999461-Security-Chain-Cinch/dp/B00X6E0NO0/] and a small u-lock that is hard to get a big enough lever in the shackle. It's not perfect but I've yet to have my city bike stolen though I don't leave it on the street overnight, it goes grocery shopping, and out to the movies and whatnot in uptown.
personally haven't used anything by hiplock. just took a look at their chains, and the included locks don't seem that beefy. for reference, this is the schlage chain i use with separately purchased lock. big price difference for what is effectively the same thing. also, i can't say i recommend wearing something like that. definitely uncomfortable for more than 20 minutes at a time. i use a chain holder thing that attaches to the bottle cage mounts. it looks stupid as fuck but it's better than on-person for me.
Check this guy out: https://www.amazon.com/gp/product/B00X6E0NO0/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
It's the same exact thing as the Kryptonite NY Cinch chain for a good bit less. You can use it in conjunction with a regular NY u-lock, or pick up one of the Kryptonite mini u-locks they sell and use that. Works great.
Naw, that’s a noose chain. It allows for a wider variety of locking situations.
Schlage is a VERY respected name in locks/mechanical security. It's no Medico, but it's a huge step up. I'm a former locksmith.