So as a former Buyer for a chain of bike shops, the majority of locks are just to keep honest people honest. Never lock up what you are unwilling to lose.

A $450 bike is probably not worth much second hand. Your risk will have more to do with the local culture, motivations, and finances of the area.

The lock is not as important as the techniques of attaching some kind of strap through the rear rim, frame main triangle, and front rim while looping them around an object that can not fail in some fundamental way.

A thief would need to air down both tires, cut the rims and bend them. If you are thoughtful, and use 2 cables, you can force them to cut the frame while being unable to get a single wheel and the drivetrain. Any way you look at it, the drivetrain is easy to steal with a hex key set. Forks, bars, seatposts, saddles, and anything else you're attaching are easy pickings too.

The specialty security fasteners are not very effective and you'll likely create far more issues for yourself when you have a flat or other issue while commuting.

So you're not really able to secure much in total if you really think out the possibilities. For that reason, get something that is light weight but can fit around rims and frame as mentioned. That will at least secure the important stuff, and do the main job of keeping honest people honest. No chain or heavy lock will prevent even a half witted determined thief.

This is why fixies are/were popular; you're building a minimalistic and cheap commuter without all the extra vulnerable componentry, while also staying light and flexible enough to actually ride hard core as a serious commuter. Getting that gear choice right is a challenge at first, but the weight loss makes up for a considerable amount of the difference even for a commute noob.

I live in a city with a pretty high rate of bicycle theft (I actually had a bike stolen a couple years ago).

Now, whenever I leave my bike somewhere, I always put two different types of locks (a U-lock and a chain lock) and never leave it outside overnight.

Seems that would be sufficient, especially since the bike would also be indoors. I’m partial to kryptonite locks, but have used OnGuard a few years back w no issues/complaints!

Get it dirty, put ugly stickers on it, etc. Make it look unappealing, it'll help.

The best thing to do well be taking it with you, even into the back of the class. Might feel weird, but it's how I kept my road bike safe all through my years living in various parts of NYC.

The U is sufficient. Be sure to lock the front wheel and frame to an immovable object. If you have a cable, run it through the rear wheel too.

Your bike might not be worth the trouble of risking to be caught stealing.

Excellent lock, I use it (and let it) at work place. No incident in many years.

Your locking technique is more important than the lock you use

https://sheldonbrown.com/lock-strategy.html

If you're worried about your bike being stolen, you could buy a second hand bike for $60 and use that for commuting. Many cyclists have a cheap commuter in addition to their nice bikes.

That bike isn't a target for professional thieves.
And opportunistic thieves will be deterred by any U-Lock.
No matter where you lock it up, there will be other more valuable bikes that are easier to steal there.

Bike locks are a spectrum, and I've generally sat on the small and light end of that. My reasoning is that any lock can be broken, it's more about how difficult you want to make it for the thief.

I'm happy with any lock that prevents someone from just picking up the bike and riding off. As soon as someone has to bring out speciality tools, they're breaking the social contract regardless of those tools being hydraulic jaws and angle grinders, or just bolt cutters. That's the step in trying to prevent.

So I just roll with a thin cable and a little padlock. Small enough to chuck in a pocket, long enough to wrap around fences/trees/friends bikes.

Your mileage will definitely vary.

I think chain locks are generally considered to be more difficult to break that u-locks. Both are equally easy to cut with large enough wire cutters but with an angle grinder you need someone else to hold the chain still while as with u-lock you can hold it yourself.

Weigh your risk factors, but overall that lock appears like a solid protection mechaism for between a frame and a bike parking stand.

The most important thing is to ensure the parking structure is secure and robust such that the lock can't be wiggled out. Never use a thin/short tree, a road sign or other thing whose bolts can easily be undone. Second, is to attach the frame, or better a tire and the frame to the bike parking structure, never lock only the wheel.

Risk Factors (you don't have to answer the questions or anything, just stuff for you to think about):

• Location: Indoors/Outdoors, Notoriety of area for thieves, urban, suburban, campus, how many people pass by the area
• When and how long: Time of day/week/year. Will it be unattended for 5 minutes vs. 1hr vs. 3hr. vs. Overnight?
• presence of streetlamp and/or camera nearby
• Value of your bike as a target: dirty/shiny? Unique? Electric or have any sensors? Saddle bags? Other accessories?
• how easy it is to remove your tire(s) and seatpost.

Register your bike in your local system if you worry about it being stolen and/or resold. In my part of the world, 529 bike garage has a program to help track, find and return stolen bikes.