I'm also interested in this thread.
When looked at Lightspeed a couple of years ago, we found a hardware / install cost of around $12k, though the software appeared capable. We didn't want the built-in ecommerce feature, and that presented some integration challenges with what we preferred for our ecommerce website.
Using Vend in the meantime, but still interested in Lightspeed. And Shopify POS.
We have been using Lightspeed for several years. We still use it in-store pending a full transition to Shopify.
If you want me to sum up Lightspeed in a few words -- it looks the deal but it is expensive rubbish.
Theoretically, it was/is state-of-the-art POS software, but in real-life it is slow, crashes often, is full of bugs and often doesn't do what it should.
Lightspeed has since moved to a cloud/desktop combo but in the earlier days you paid for the product up front (thousands of dollars) and then paid yearly "maintenance" fees (many hundreds of dollars) which essentially entitled you to software updates.
This wouldn't be so bad if the updates contained impressive new features. But mostly the updates fixed things that didn't work that you had already paid for or broke things that did work that you then had to pay for to get fixed.