It is less painful initially, but takes a week longer to heal. So if you have a high powered dog that needs to get back to work quickly, go for the traditional method, and ask the vet for some good pain meds for the first couple of days back home.
Just my opinion but for this type of surgery I think that it is more of a gimmick, it's only a single short incision.
They also need to push it to pay for the unit and justify its purchase.
Whichever way you have it done ask them to place absorbable, buried sutures as you will get less irritation that way.
I use laser everyday and disagree that it heals slower, UNLESS it is used at too high a setting and then there can be extra tissue damage. For such a short incision the benefit of decreased bleeding and swelling are minimal, but for bigger, older dogs the decrease in bruising and swelling can be significant. I would prefer to use it, unless they use it as an excuse to charge a lot more. Also agree with buried absorbable sutures, nothing exposed to lick on. Preventing excessive licking is a bigger issue to get faster healing, even with buried sutures. Forget the big E collars, if you need to stop licking. Use a plastic bucket just long enough to get past their nose. Cut a hole in the bottom for their hear. Line the edge of the hole with pipe insulation and attach with zip ties. Then have a 4-5 holes above the insulation to tie to the collar with old shoelaces. I got this idea for an ophthalmologist when one of my dogs needed eye surgery. She learned to back into her crate for the 10 days she needed to wear it. For a neuter 5 days is probably enough, and it is easier to take on and off.
Also, I do not believe in neutering until they are over 14 months of age, let them mature. If you are on this forum, chances are you are responsible enough not to allow roaming and indiscriminate breeding. There are medical reason to let them mature.