...........I have been looking around quite a bit and seen numerous models of staplers and cleat nailers. I will be installing about 80 sq. ft. of 3/8" Brazillian Mesquite over existing (presumably oak) hardwood. It appears that virtually everything that is designed for 1/4" to 1/2" hardwood is a stapler rather than a cleat nailer. It also appears that the rental yards only carry equipment for 3/4" such as large Senco and Bostitch models like the Bostitch- MIIIFS or Senco SHF15 or SHF50.
...........The Bostitch LHF97125-2 and the Bostitch S3297LHF2 have conflicting descriptions that in some cases state that they are for "Laminated Hardwood" and in some cases state that they are for "Solid Hardwood".The Senco SLS20HF says that it is for 1/4" to 1/2" hardwood. Will any or all of these work for my application? Is there a benefit of one over the other for my application? I already have an older model Power nailer manual cleat nailer, will that work as well or should I just forget that option?
............Please give me some guidance based on someone actually usuing these products as the manufacturers sites provide little real help.

Most engineered staplers or cleat nailers come with a 3/8" base shoe and a 9/16" base shoe...then adjustibility in the base shoes itself for proper staple or nail placement into the slot above the tongue. I like the Spotnail engineered flooring tool that is silver and blue but that's mostly because a certain manufacturer(that I tend to do alot of work with) reccomends that particular brand with their staples.

Stanley-Bostich also make a stapler for 3/8" engineered as do Powernail, Senco,Portanailer and others. One thing to watch for is dimpling of the top layer of the wood as the staple will create one if you don't have the tool setup to drive the fastener at the proper angle.

Thanks for the information, but I am still not clear on whether it makes a difference whether I use a cleat nailer or a stapler for 3/8" hardwood. Can I use the same gun (with the correct shoe) for any type of flooring (ie solid hardwood, laminated hardwood, engineered flooring) as well as any thickness of flooring? All of the information that I read gives me conflicting answers. I have a porta nailer 401 cleat gun, should I use it, or get a stapler. If I get a stapler, should I get one that says it is for laminated flooring even if I am installing solid wood? The rental yards near me have the Senco SHF15 and SHF50 which are both cleat nailers. Or the Bostitch MIII which is a larger combo cleat stapler, but all 3 of these say that they are for 1/2" up. The Bostitch staplers as well as the spot nailer say that they are for "laminated" but don't mention solid. Does it matter?

I use a Spotnails stapler with a narrow crown staple. The gun has adapter plates for 3/8", 1/2" and 9/16" flooring.

Is this a solid or engineered? What can happen is the heavier 15 gage staples with a 1/2" crown can cause a dimpling effect that will readily show up in certain lighting conditions.

Check with the mfg. on what fastener to use.