I've owned two Reef Octopus HOB skimmers in the distant past, and they never gave me any problems at all. I've never owned an SWC skimmer, HOB or otherwise, so I can't attest to their build quality.
As for your lighting solution, a 150w MH pendant should be more than fine to keep just about any type of photosynthetic coral species. For years I kept a 150w pendant above my 25G cube and I loved it. There are just a few things you need to consider when you use this type of lighting solution, however:
1.) You'll need to adjust the height of the pendant in accordance with the type of coral species you intend on housing. If you keep strictly high light loving coral, and you want to place them at any depth within the aquarium, you'll most likely need to keep the pendant closer to the waters surface so that the coral placed towards the bottom of the aquarium get the light they need to thrive. But be careful that you don't burn any of the coral you place closer to the top of the aquarium. Keep in mind that unlike LEDs where you can adjust the intensity/luminosity of the light fixture with a simple turn of a knob or push of a button, metal halides can't do this. So the only way you'll be able to adjust how much or how little light you provide to your aquarium, will depend on how high you suspend it above the waters surface.
2.) Metal halide lights produce considerably more heat than any other type of lighting solution in the hobby. It may just be an oversight at the moment, but you should definitely keep it in the back of your mind that at some point you may have to think of a cooling solution to offset heat produced by the metal halide so that it doesn't affect the temperature of your aquarium.
3.) Unlike LEDs, which have a ridiculously long lifespan, for the most part of course, metal halides need to have their bulbs/lamps replaced every 7-12 months, depending on the types of bulbs you buy, and also depending on how efficient of a ballast you run.
Anyways, it looks like you're off to a good start. And I'll be keeping an eye on your thread to see how you make out. Best of luck to ya, and remember to always ask questions!