Well, I wouldn't call them junk. Onkyo has been delivering reputable entry level systems for years, and the HT-7800 offers a 8 input HDMI solution along with other features that are tough to beat for the money.
So, given the choice between a Bose system, or a soundbar, or some other HTiB that doesn't include a powered subwoofer in the package, I would take this in a second. But, that said, 'tough to beat' and 'impossible to beat' are two different concepts.
I would take some time looking around for deals that may provide you a better overall system for the money and take some time listening to different systems that are out there. You may want to consider going with a good stereo setup first with a decent A/V receiver. Accessories4Less.com often has some very good deals as well which you should take a look at.
But, instead of jumping into a HTiB system right away, it may be better to do some intelligence gathering and see if that's actually the best way you should go vs. piecing a system together in a different way.
Start with your budget. Maybe lower your budget a bit as people like to go OVER your budget all the time it seems. You also would need to include some wiring for your room. While not pricey, it needs to be included. As well, you may need cabling for components. Once again, not that much money.
Also worth noting that the 3800 is $500 and the 7800 is about $900. That's a pretty significant price jump. So, if you have some flexibility in your budget, it may be worth noting that. It's easy to spend thousands on A/V gear, so be prepared if your goal is excellent sound. If your goal is the best for the money, then be honest of how much you want to spend.
