OK so the thread says 'best' but it also says '18-20v' and 'cordless drill' Nobody will deny the M12 Fuel impact driver is the best, but 1. you can't get it yet and 2. let's back up for a sec. We're getting a little carried away.
I assume
this impact driver will go with your current set of hitachi batteries? For those screws, the important thing isn't the fastener, it's the hardwood they're going into. They're tiny, right? You need a tool that will get a tiny screw into hardwood. Try this one, if it works you can still use your existing tools, you're only out $100 or so if it doesn't work.
If you need to change brands or go up to 18v, at least you made a logical attempt at saving (I assume 'the company' since you said guys at work) money before jumping to something totally different.
If it's the employees buying their tools and they want to buy something else for it, then pass along the M12 Fuel is 'the best' or go up to pretty much any 18v
however I still recommend if you have to go up to 18-20v, still probably best to get the drill/driver & impact combo, just giving someone an impact driver and saying 'go drive the same stuff you were with a 12v drill' not going to come out with good results until you give them a few tries.