Is trazodone effective for sleeping?

Yes. I see my colleagues endorse trazodone only cautiously, but I've had good success with it in my practice. It's non-addictive (unlike many sleep aids), the dose is easily adjustable, and it's long-acting, so it gives a full night's sleep. It's not quick-acting, so best to take it a little ahead of bedtime. Side effects are rare in my experience.
Sometimes. Many people take trazodone for sleep. As with any medication it can have side effects, some serious (priapism or painful erections, inducing a mania in someone with bipolar) so make sure that you are following your doctor's advice. Generally trazodone is only moderately helpful, its main problem is that many people report a hungover feeling the next day.
Trazodone. Caution if mood swings or taking other medications that add to sedation, constipation, dry mouth, blurred vision.
Short term only. Used alot in elderly nursing homes, not particularly good for more than a few days, less rem sleep, but cheap.