No one can really say with 100% certainty which brands are good. That is almost purely subjective. There are some commonly accepted bad brands though:
Lamar (their 2011 stuff I hear are getting better though)
The most popular brand in this forum is NeverSummer, but their boards are well out of your price range.
These are brands that I like in no particular order:
Rossignol (only a couple of their boards)
With your price range, there are some good options for you:
Snowboards Size 155cm-158cm : Price 300:399
My top recommendation for you out of that line-up is the K2 Raygun. For the price, you get a ton of quality. It is an Intermediate all-mountain board, but that is a good thing. With beginner boards, you'll quickly outgrow them. The Raygun isn't going to be super stable on steep runs, but you don't have to worry about that for a while anyway. By then, you'll probably want to add another board to your collection anyway. It's a mid-flex board so it is versatile. It'll be forgiving enough to learn on, yet stable enough to tackle blue runs when you get to that point. Also, if you find yourself becoming a powder junkie, the rocker profile on the Raygun is going to be sweet. That brings us to the next benefit, the rocker profile will help with reducing edge catches while you are learning. However, it's not a true rocker (it's actually flat in the middle) so it's not going to make you learn bad habits.
The other board I recommend out of that list is the Darkstar. This one is a bit stiffer and is completely flat camber. This board will be more stable on steeper runs. However, it has a Sintered base which means it is a lot faster than the Raygun. I forgot to mention the extruded base on the Raygun. Extruded bases are less maintenance, but they are slower than waxed sintered bases. Sintered bases need to be waxed more often to maintain their speed. Extruded bases are faster than an unwaxed sintered. With that said, because extruded bases are in fact slower than a waxed sintered, they could actually end up being more maintenance if you want to squeeze the most speed out of your board. You'll find yourself waxing an extruded base more often than you would with a sintered.