OK, time for some specifics to back up my gripes.
bubblevision - which camera and L&M housing did you have, and did you buy it used?
It was the Sunray II housing with the Sony TRV40 which is a TRV50 without Bluetooth. L&M told me the Sunray II would fit it. I bought the housing new from Armatos, shipped to Singapore.
RED FILTER
I have never heard of a problem with these, but missuse of solvents can ruin any plastic parts.
I've never had any solvents near it. It's just a totally crap moulding. In my view it should be stronger and moulded better, or aluminium like the Gates one. In normal use mine cracked along the knit lines in the moulding:


WET CONNECTORS
This is a maintenance issue, due to corrosion and bad conductivity on the wet connectors. Keep them clean and use a light coat of dielectric grease (silicone o-ring grease is great) for good conductivity and to prevent future corrosion.
I always wash my gear thoroughly and I tried greasing them, cleaning them etc. etc.. But it still always seemed to be a case of 50/50 whether they worked or not. I could never rely on them at all. Also the cables fatigue through really quickly where the "strain relief" section thins down. In contrast the EO connectors used on Amphibico lights and Gates external monitor just work and carry on working. I have suggested to L&M that they switch over.
LIGHT BATTERY FLOODS
This is a maintenance/missuse issue. If there had been a problem, L&M would have replaced them.
I have had no fewer than 3 floods on my Sunray 2 battery pods. In each case there was no clear reason why the pods flooded. I always keep the surfaces clean, grease the o-rings and so on. I don't know what else I'm supposed to do! In my view the asymmetrical "kidney" shaped cross section of the sealing surface is just silly.. It's asking for trouble. At least on the old Sunray 1 pods the design was symmetrical. Flooding an L&M battery pod is no laughing matter. You're looking at something like $150 for the battery, $150 for the PCB, plus shipping, tax etc.. All 3 times I was without the lights for months and my season was badly affected. I sometimes feel these lights have taken years off my life 
CAMERA DIDN'T FIT
There has to be more to this story. L&M housings will fit all listed cameras and batteries. Either you didn't have the right camera or battery, or L&M would have fixed it if there was an issue.
The camera fitted fine in my bedroom. But as soon as I got a few metres underwater it was no longer possible to operate the blue water filter. It just hit the outside of the camera lens instead of going in front of it. They hadn't allowed any space in the design for compression. In the middle of a busy season I had no option but to modify the housing myself to make it fit by fettling material off the electrical connectors at the front and back of the camera tray, and off the filter arm.
MONITOR BACK
When the monitor back arrived the PAL/NTSC switch was just completely missing:

Probably just a shipping problem but the exposed design is inviting trouble. I've since had the switch replaced by L&M and after a few dives the switch itself fell to bits. I've had to solder the contacts closed in the PAL position.
As for the monitor itself, after a couple of years it just died totally for no apparent reason. I don't know why. L&M fixed it (can't remember if they charged but I was without it for months) and now it works but there are diagonal lines across it that weren't there originally.
CAMERA TRAY LATCH
The screw in that thing is tiny and too short. Mine has come to bits numerous times. Again it's a fiddly little detail that would be so much better if it was more ruggedly designed.
Here's some more...
BATTERY PODS FALL APART
I've seen this happen on 4 different L&M battery pods (3 of them mine). Why they can't glue them properly or at least tape them is beyond me.

On top of all this the service times do seem to be getting slower and slower. I guess they're just busy. Plus one time I asked them to discuss shipping options with me before they shipped, but when the time came they just charged my card and shipped. Recently again I asked them to wait before actually shipping because I wanted to order a couple of minor parts at the same time, but when the time came they just shipped. It's like they don't talk to each other or they don't have a way to attach notes on screen to their service jobs. Seems a bit ironic when their recent "meet the team" newsletter talked so much about committment to great service.
To end on a positive note, L&M stuff is great when it works. They are brilliant at aluminium extruding/casting/machining, the housings handle very nicely, their lamp heads are superb, and their optics are excellent. I like their lights so much (when they work) that I even bought a 2nd set so that I had plenty of backup, and Conor from the their sales department took pity on me and very kindly let me have them at trade price. So it's not all bad. Plus the housing itself is currently stable and actually making us some money on daytrip vids 
Anyway SomeAssembly, I'm sure mine is an extreme case and I wish you the best of luck with your housing. At least you are in the USA if things do go wrong.
Nick