Experts agree that no bike lock is impenetrable. However, some locks resist would-be thieves better than others. U-locks are better than cable locks, but the toughest ones tend to be expensive and heavy. The top-performing Kryptonite New York Fahgettaboudit U-lock, for example, costs about $65 and weighs close to 5 pounds. However, if you're on a budget, some reviewers say the OnGuard Pitbull STD 5003 U-lock, which weighs about 3 pounds, provides good value for a reasonable price. Tests show it's able to resist attacks with hand tools, making it better than many other U-locks and far better than any inexpensive cable lock. On the downside, tests show it can be quickly cut with power tools, and the anti-theft warranty is void in New York State (as with all bike lock anti-protection plans). Many user reviews are not as complimentary about the lock, with owners having reliability issues fairly quickly after purchase.
Australia's Ride On magazine has the best comparative review of the OnGuard Pitbull STD 5003, showing how well it resists attacks compared to others. BikeRadar.com (from the publisher of Cycling Plus magazine) also rates this product favorably after testing, giving it an above-average rating.
This short review judges the OnGuard Pitbull STD 5003 to be a reasonable value. It holds up well in hand-tool attacks, but doesn't put up much of a fight when confronted with a power tool.
Review: OnGuard Pitbull STD 5003, Warren Rossiter, June 22, 2007
More than 30 owners review the OnGuard PitBull STD 5003 on Amazon.com, posting favorable comments about the lock itself. However, some report difficulty with the mounting system, difficulty with unlocking, broken keys, and the lock breaking or cracking after only a short time.
Review: OnGuard PitBull STD 5003 Bicycle U-lock, Contributors to Amazon.com
3. Ride On magazine
Of the three OnGuard locks included in this Australian magazine's test of 11 cable, armored cable and medium-security U-locks, the OnGuard Pitbull STD 5003 holds up best. However, other locks not available in the U.S. resist attack longer.
Review: Lockbusters, Mark Horner, Feb./March 2007