i own almost every wavelength of lasence and optlaser modules available, i can say, they are really nice modules, the 545s are a nice lime and i really like the 1w one thay have, the 551nm/555nm modules are really bright so they are good for things that you need a high brightness laser at a lower power (idk if they still produce them anymore), the 561nm small 2-9mw modules are really good tiny yellow-green dpss lasers measuring only 8mm in diameter they are really good for pointers and applications that need a small, bright and low powered yellow-green laser module. the bigger and more high powered 20mw 561nm module is less on 561 and more closer to 558-559, but they are still really good modules if you need a big and very bright yellow-green module. i feel like the 575s need some work done to them as they have extremely hygroscopic crystals and one mistake can damge the whole thing, also it needs a better driver, but it is good if you leave those things aside, i love the pure yellow and the high power (10-20mw) makes it better, now about the high power lasence lasers, if you have looked carefully on their alibaba page, you would see some very high power dpss lasers (most are 1-2w but some are up to 13w) the only high power lasence laser i own is the 1w 545nm dpss laser, its a really good laser (if you have the money to buy them as some are really expensive) it is very bright, but the laser light comes strait out of the crystal so it has a very high divergence and it is in tem01, these high powered ones are ir filtered unlike the other low power ones. i hope you liked my review on the lasence modules