For many years I had been a big fan of EV gear (the cabs with wooden boxes, not the plastic stuff) and had been really pleased with the sound quality and reliability. Then about 2 years ago after a great deal of research taking into account cost, weight, size and all of the other factors I changed over to Logic System. Our current rig now uses a 1 x 12" + horn top can and a 2 x 15" bass cab each side and wow, what a difference. I'm now in the process of changing all of the monitor cabs to Logic System as well which speaks for itself. The rig is used by an 8 piece soul and Motown functions band with everything going through it so you'll understand what it needs to handle.
For sure there are better systems out there such as Nexo, Meyer, etc but pound for pound I seriously recommend taking a look at Logic (the older series). But probably the most important factor to consider in whatever system you end up with is that everything needs to be set up right. As it seems you are going for the passive route (which is my preference any day of the week) then I strongly recommend that you use an active crossover and bi-amp the rig. This approach is streets ahead of any passive crossover system and really lifts the overall sound quality and dynamics. The down side is that you need an electronic crossover or LMS (loudspeaker management system) and a second amp to drive tops and subs but this does maximise the potential of the system.
Once you get to this stage you need to ensure that the crossover or LMS is set correctly to match your power amps and the speakers. The benefit with using something like Logic, Martin or Nexo is that they will have produced active crossover networks or system controllers to run with their speakers so you can either go for a turn-key solution with one of those or if you choose the LMS route such as a DBX PA Driverack or the Behringer equivalent then you can talk to the engineers at Logic or Martin, get the correct settings off them, program them in and away you go. I did exactly this with my Logic System rig and I was truly amazed how it made the rig come alive. It sounded good before but sounded brilliant afterwards.
If you go the JBL, Mackie or random speaker box route I fear you may have a bit of a struggle on your hands to get this sort of information from them - I don't know as I've never dealt with them direct. And to play around yourself or get an experienced sound engineer on the case could take you quite a few hours or even days to get the system working at its optimum level.
As you've intimated, second hand is the way to go (which is what I have done) and with a bit of patience and careful shopping around you should be able to put together a nice system without having to re-mortgage the house, wife, dog and pet rabbit!
Btw, if you want to do some research on Logic gear a useful tip is to Google 'Logic System' and then Logic Systems'. The singular is the correct name but many folks use the plural and this will help come up with a completely different list of hits.
Welcome to the wonderful world (and minefield) of PA systems.
Col