The Light & Motion Urban lights are very good. A little more expensive than some but worthwhile for the quality and US designed and assembled product, with good customer support. I've used a L&M Urban 500 for about six months and have no serious complaints. I can see room for improvement in a couple of features, but that's true of almost any product.

If there's an REI in your area they should have a display board with bike lights you can try and compare. I bought my L&M Urban 500 from REI after spending about 30 minutes or so comparing various bike headlights. Then I went back a couple of weeks later and bought a Cygolite Hotshot 50 after comparing their display taillights.

Keep in mind that in actual practice most bike headlights at any given price point will perform very comparably. While the online light comparison tests will show what appear to be significant differences, those are unintentionally biased by the limitations of still and video photography, which have limited dynamic range. A healthy human eye with average visual acuity will tend to ignore those minor differences.

In real world usage I see very few differences between the diverse range of bike headlights used by dozens of cyclists I meet at local nighttime group rides several times a month. Pretty much any self-contained bike headlight costing $50-$100 will cast a very similar beam in terms of brightness and coverage. Light & Motion, Serfas, Niterider, Cateye, Cygolite, etc. -- they'll all very comparable at night on the ground to the human eye.

My Serfas SL-255 casts a much narrower, more spotlight-type beam that's quite bright in the center for only 255 lumens. I use it on the MUP at night to avoid blinding other cyclists and joggers. It has remarkably little spill. In contrast my L&M Urban 500 appears brighter but has a much broader beam that can blind oncoming cyclists and joggers (I've seen some joggers and pedestrians shielding their eyes and looking annoyed, so I try to aim it downward or use the Serfas instead). But the L&M is great for my rural rides in very dark areas, and in the city where it must compete with bright car headlights.

There are a few lights with significant differences: the Light & Motion Taz lights, which have a broader, more diffuse beam that appears slightly less bright to my eye than my Urban 500, despite the Taz being rated as more powerful; the Busch & Muller Ixon IQ, also emphasizing a more broad and diffuse beam without the spotlight effect common to many US market headlights (B&M can be ordered easily from German -- they do their best to make it easy with exchange rates and shipping that are very competitive); the most recent Serfas E-Lume lights with dual LEDs. But those all cost more than your $50 budget. And you can get a very satisfactory light for $50.

So get the one that appeals to you. Pretty much everyone I meet who has a different light seems to like his/hers just fine.