I know nothing about the Laguna lathe. But I do own a powermatic 3520b. My wife bought it for me for Christmas quite a few years back. I love the lathe. It has done all I needed it to do. They also have great resale value if you ever decide to sell.
Today being said, I am starting to investigate a one-way or robust lathe. Have turned on a robust and they are so smooth. Have always wanted a one-way, so not sure where this will lead to.
I owned the PM 4224, now I have the Laguna REVO 1836. I much prefer the Laguna over the PM solely because of the height. Both are awesome but the PM was too high for me to turn, my arms got very tired very fast. Guess I could have built a work platform but I opted to sell the PM and purchase the Laguna. Either way if you are tall enough to turn on the PM, it is an awesome machine. If you are too tall for the Laguna, you can install the 3" riser. I would go for which ever is the less expensive one, you will be happy with either.
I have a powermatic 3520b which has been a great lathe for me for around 10 years, but that's completely useless information for you unless you have a chance to buy a 10 year old 3520b. Tools and tool companies change over time. A few get better and many go the other way.
If I had to replace my lathe today, I would not automatically buy another 3520b. I would not buy any lathe in the price range you are looking at if I had not had a chance to turn on one for a reasonable test period. Would you buy a car without taking a test drive? You are talking about a serious investment. Some things can only be learned by using the tool. I knew a guy who got a oneway lathe as a gift from his wife (lucky him!). It was a fantastic lathe, but he hated it. The tubular construction caused some sort of weird resonant sound when he was using it and it drove him nuts. Most other turners in the club couldn't hear the sound. But some could and some of them found it super annoying.
Craft supplies offers turning classes. If you are going to buy at craft supplies I would think they would let you take some classroom lathes for a spin. If they don't have newer models of what you are considering in the classrooms, that might make you think twice. If you belong to a local turning club, you can probably find an assortment of lathes to take for a test drive.
10 years ago when I bought my PM3520b, Powermatic customer support was top notch. A couple of years ago I tried to contact Powermatic customer support and the experience was completely different (not in a good way). I would compare the warranties on the machines I was considering and then call the customer support lines with a "test" support question.
I don't know anyone with a Laguna lathe but I know many with the PM 3520B.
The PM seems to be the go to and most sought after lathe before one goes to the OneWay, Robust, Vicmark, etc route.
The PM 3520b lathes that come up for sale are often sold sight unseen. They are are a very solid lathe and a workhorse.
I found one on Craig's List, contacted the seller that morning, told him I would take it dependant on inspection when I came to see it. I went to the bank, contacted a friend to help me load it and was planning on going the next morning with cash and my trailer. By mid day, the seller stopped communicating with me. That evening, I sent another text......he said the lathe was sold.....no apology.
Today, I found this lathe review. It is rather long but a good read. Maybe it will help with your decision.
The Powermatic lathes are Cadillacs...the Laguna 2436 is a Ferrari. I've used both but own a Laguna. Powermatic makes great jointers and tablesaws. For bandsaws and lathes Laguna has the edge...plus, their customer service has been unequivocal among my industrial machines.
It's like the Stihl vs Husqvarna debate. They both own 50% of the market...it comes down to personal preference.
Happy turning, Gents.