As laser and optical technician for close to 15 years now with 9,000+ repairs, calibrations and QA checks under my belt, I've seen quite possibly every brand and model of laser on the bench, inside and out.
If you'd asked me 7 years ago which laser level was the hands down best unit I would have had 3 different suggestions - The Japanese built Sokkia's LP31 a successor to Sokkisha's rock solid LP3A, The iconic top heavy Spectra Physics LL500 from Dayton, USA or Laser Reference's L4 out of the modest factory in San Jose in California.
These lasers had three things going for them:
Accuracy: Using proven technology from high-end optical surveying instruments they were hand assembled by skilled technicians to produce some of the most accurate lasers ever built. They had temperature and vibration compensation as standard.
Serviceability: All parts were available. Every screw, prism, piece of glass, and wire was replaceable. Write-offs were rare and the reason that these units are still in service today, 20 years on.
Efficiency: Good design and minimal moving parts meant these laser all clocked over 100 hours on one set of batteries.
So, what happened? To save costs Sokkia stopped manufacture of the LP31 and LP31A shortly after the company was acquired by Topcon, opting for a Topcon's servo driven solution. Spectra Physics was acquired by Trimble and started manufacturing the LL500 in China, parts were reduced to complete assemblies and the unit lost is serviceability. Like other, similar, industries, we've seen an influx of manufacturers coming out of China and parts of Europe where labour is cheap. Two things happened, 1. The big names see an opportunity to increase profits and move manufacturing abroad and 2. Factories re-badge and re-brand the inferior OEM products causing a significant increase in the amount brands available. The laser industry, once filled with a few specialised manufacturing companies is now diluted by 100's brands that pollute the hardware stores. $49.95 specials that lull the consumer with promises of accuracy and reliability.
So how do these units look in comparison to the classics of the past, Let's take a look:
Accuracy? Opting for a motor driven levelling system, moving parts are increased, the need for skilled labour is removed and as a result - accuracy in compromised and Temperature and vibration compensation is removed.
Serviceability? A tool for life? Nope. Expect to replace a dropped unit. In fact with all the moving parts, there's a good chance you won't even need to drop the unit before it fails...
Efficiency? You would think that with the evolutionary leaps and bounds of the battery industry we'd see an improvement here. Unfortunately, with all the moving parts, your looking at more like an average of 30 hours run time. That's right, 70% less out of a set of batteries.
So where does that leave us? We'll, hundreds of brands but seemingly very little choice. A prospective purchaser you could throw down $3000 to 4000 for a premium product from Trimble, Leica or Topcon - which might get you close to the accuracy, serviceability and efficiency that we took for granted but why should we have to pay more for what we had before at a reasonable price?
The good news is, we don't. It turns out after all these years that the modest Laser Reference factory in San Jose, California never stopped making lasers. Hand built, highly serviceable and even better accuracy than before - They even look the same! To this date, you can still buy a Proshot L4 (now the L4.7) with the same repair ability, better efficiency and better accuracy (7 arc seconds or 1mm of deviation per 30m).
If you want to buy one laser level that's going to do the job accurately and keep doing it for years to come - the choice is actually easier than ever before.