I have heard the LH500's can get a little wooly if you push the volume past 2 o'clock. You may need to be pushing an 8-Ohm cabinet if you want to be in the same room when this occurs. You can also try kicking in the Limiter because that's frequently reported to be a bit of a power-soak as well.
As I have an LH1000 and a 4-Ohm cabinet, there's no way I'll be running the volume up to 2 o'clock unless I'm playing a venue with 'Stadium' in its name (unlikely...).
Hartke was actually #4 on my original list when I went researching for amp shopping originally. Heard a lot of good stuff about the Aguilar Tone Hammers. Most reviews concluded the built-in tone is great if you love it, but it's there to stay. So too with the GK's (actually, a GK Fusion 500 is still on my list as a small-venue and backup amp). The MarkBass had the reputation for clean & clear but were having some reliability and parts availability issues at the time. (I hadn't heard of Glockenklang at the time but they'd be on my list today...)
But the point is - you can "dirty-up" clean, and you can do it -exactly- how you want for the tone in your head and the project at the time. You just can't clean up a baked-in tone if you don't like it. I kinda envy the Ampeg and Tone Hammer guys because it's a one-stop shop -if you love that tone-. But I need that crystal-clear tone -and- some vintage tubey when I want it.
For the 'warming, tubey, vintage, OD' vibe, I'm partial to the Darkglass stuff; I have a B7K that can get me that 'Vintage Cream' Jack Bruce tone and I expect I'll add a Vintage Microtubes Deluxe as a further refinement on that Marshall classic rock sound (VMTD not yet available when I bought my B7K...).
The LH's offer a great value in tons of loud, clean headroom in a rugged rackmountable package. I think of it as an integrated pre- and power amp, ready to go. At a remarkable value price point. If I want the ToneHammer tone, I can just go buy a ToneHammer pedal and be 90% there (the drive circuit is a little different). Or one of the DarkGlass offerings. All of these options are true preamps and _can_ completely replace the LH pre section if you want, or in case of something like tube failure (rare, but it happens).
Start with a clean slate and add the dirt you want, when you want. You're still $$$ ahead...