Have used Ortlieb bags (rear panniers and handlebar bags) for years. I like the engineering and they seem indestructible. For touring they are hard to beat. I like the key & lock option but find that most of the time I unclip the handlebar bag and bring it with me when I'm off the bike. One idea is to purchase several mounts to install on different bikes to enable you to use the bag more often.
This is our 2nd one of these handlebar bags. Our first was 6 years ago and now I got one for my wife. My only issues is one, you now have to buy the mounting kit as a separate item and two, the cable that anchors it to the bike is now much thicker and harder to bend around the twists and turns to anchor the device. What I really like is how easily it comes on and off the bike's handlebar.
The Ortlieb ultimate six handlebar bag is great. It has the room to hold my essentials-snacks, clickstand, inhaler, wallet, phone as well as a sun shirt or light weight jacket. I could hold more-the space is there- just trying to balance the weight. I wish it had an attachment on the outside for my phone or GPS.
Works as advertised. Roomy and study.