You probably don’t think you need a laser level. That’s what I thought too. Boy was I wrong! I, now, consider it one my most useful tools. And the best news of all, they are not that expensive.
Initially I decided to pull the trigger on a laser level when we were putting up our kitchen cabinets. Both the upper and lower cabinets are mounted to the wall by a horizontal rail that is screwed into the wall. In the Ikea system, this rail has to be perfectly level to ensure that the counter is level for the base cabinets and to align all the bottoms of all the upper cabinets. Now I use it for almost every construction or decor project we do. I use to to make sure hanging pictures are aligned or curtain rod supports are aligned. I used to to cut the deck posts at the same height (you can read more about the deck construction here). I even used it at a friend's house to mark the straight vertical line to where we were demolishing a wall to. Basically, if I ever need a straight line (horizontal or vertical) or need to align or mark something that is longer than my 4’ level - I whip out the laser level. I have even found it to be more accurate than the 4’ level.
I started my research by looking at brands and ultimately decided on Bosch. I already owned a Bosch laser measurer which I got for doing as built drawings of buildings as a side gig when we lived in San Francisco. Bosch is widely considered to have extremely good laser technology.
There are several different types of levels on the market. First there is color - red or green. Green is easier to see but it costs more. There are some levels that have a rotating mirror in that them that allows the beam to be 360 degrees - these are also more expensive. I wasn't looking to pay a lot of money for a laser level but I did want to feel like I was getting something that was good quality and useful. Ultimately I narrowed my search to the Bosch GLL 30 and the Bosch GLL 55. Unable to decide between the two and unable to find reviews of comparing the models, I ended up ordering both of them to do my own comparison. You might be expecting to find a long review and photographs showing the comparison, but that is not the case. I very quickly realized that the GLL 55 was vastly superior to the GLL 30. It was brighter and had a wider beam spread of nearly 180 degrees. It was definitely worth the extra money to for the GLL 55. And it hasn’t been a purchase I regret. Like I mentioned in the beginning, I use it for nearly every project - picture hanging to demolition.
Since I made my purchase, Bosch has released a green laser which I would have considered at the time I was looking - Bosch GCL100-80CG. Not only does this have a green laser, but it also has a rechargeable battery which is quite handy and even more so if you already own a 12v Bosch tool or are looking to acquire one. The Bosch GLL 2-20 is another model I would consider too. This one is especially handy for the 360 degree horizontal laser. For me, at the time I didn’t feel that the 360 degree horizontal laser was worth the little bit extra. Now, I might reconsider that.
Here are all the levels I linked above: