Pros:
- Affordable
- Reliable, with easily accessible replacement parts
- It works really well
Cons:
- You might need a separate skimming solution
- The hose takes up a lot of space
Watch out for:
- Acorns and other ridig debris may potentially jam the impeller
Verdict: 
The Hayward PoolVac XL is a suction driven automatic pool vacuum. Suction driven pool vacuums connect to the pool's skimmer and the force of the water flow is used to driven the vacuum's movement. This is an older design than you would typically see from a robot pool vacuums. Generally, the most common modern design has similar functionality as say an older version of an iRobot roomba where the vacuum itself is powered and uses a random path to cover the entire area of the cleaning space. These robot vacuums are either corded or battery-powered with some battery powered units having an integrated solar panel. Most of these modern-styled units do not empty their wastebins, which means that is up to the homeowner.
I actually inherited my Hayward unit with the home I purchased a few years ago. My home was generally not well-kept and required very heavy renovations. Due to this experience, lets just say I do not trust the previous owners' judgement very much. I've thought about replacing this Hayward unit countless times, and I've done considerable research on the other vacuums on the market. I've reluctantly come to the conclusion that this is probably the best solution in terms of maitenance and value. We have abused this unit and it just keeps working with very little maitenance. There's no battery to charge and you do not have to empty an internal wastebin. The unit cleans the sides and bottom of the pool automatically with no fuss. It just works. My unit is very old, and Hayward has been selling these particular vacuums for quite a while now. Check out this video on the PoolVac XL from ten years ago. There have been no material changes to the product since its inception. The thing just works.
Its also much cheaper than newer style units. It'll cost you roughly $350 give or take, which is about the least amount you can spend to get an automatic pool vacuum. A quality unit with a modern design will cost north of $1000. You might be able to get a decent corded unit for around $800, but you may sacrifice some quality.
Another price-saving perk of this unit, is the fact that you can buy parts for it. Just about every part of the unit is replacable. I spent roughly half the purchase price of the unit and replaced every single part on it with just a screwdriver. This unit will outlive you, if you take care of it.
Parts List:
The downside of this unit is that it is bulky with the hose attached. You are supposed to remove it from the pool before swimming, which can be a hassle. Additionally, it requires storage during the off season. If you are severly limited on space, this product might not be your solution. Another pitfall of the unit, is that it attaches to the skimmer. This means that the skimmer will not skim your pool with this vacuum attached. If you plan on leaving it attached most of the time, debris that falls into your pool will need to saturate and sink to the bottom before being picked up by the vacuum. Alternatively, you will need to switch occassionally between skimming and vacuuming, which is not exactly effort free. I ended up purchasing a separate solar powered skimmer robot to skim the top of the pool while this Hayward unit cleans the inside. This setup works quite well for me. Occassionally, the robot skimmer gets caught on the hose for the Hayward, but as long as the unit is running and moving this lasts only a short duration. I have run the skimmer robot without the Hayward PoolVac XL and it actually gets caught from the pool's skimmer suction itself, which is probably worse.
In conclusion, I think this is a valuable product that punches above its price point. It will not buy you a maintenance-free pool experience, but it will certainly save you plenty of time and effort.
Here are the Amazon reviews for the product:
My Hayward PoolVac in action:
