James,
I used to have a total Hartke set up; 7000 head, 4.5 XL, 115XL, and the tweeter array (I'm not sure of the nomenclature - it had 4 5 tweeters, I believe). I didn't have Alembics then, but I used it with my other instruments (primarily my '73 Fender Jazz and my '79 Musicman Stingray). I can't speak to the weather effects on the aluminum cones, but I found it to be fairly versatile and bullet proof. I ran it via the built in crossover and biamped it. Worked great for me, until ...
I tried an Ampeg SVTIV Pro and BXT series cabinets. That did it. I sold my Hartke rig, and bought an SVT IV Pro, and BXT410HLF and BXT115HLF cabinets. I found the tone to be superior with the Ampeg, but that's just me. Also, the Ampeg cabinets have an attenuator built in for the tweeter which I find useful in certain situations.
Would you go wrong purchasing Hartke? Not from my experience. It's well built and you can achieve many different tones.
What I think is more important is adding an SF-2 to your rig. I run mine through my SVT IV Pro and it is just incredible. It does wonders for your tone shaping. Regardless of what amp/cabinet set up you choose, start saving the money for an SF-2. You won't be disappointed.
Good luck in your search,
Alan