Well, the problem is that there arent any really "bad" brands. Every company makes a cheap, good, and $$$ regulator. Some have features unique to that regulator or company (such as Mares/Dacor VAD or the Oceanic/Aeris DVT).
Before I start spewing out brands and types, give me a rough budget to work in. I can name one regulator, that will beat out a $1500 reg in performance but runs around $400, but that is out of some people's budget. My advice tends to be: go with as good as you can afford in a regulator, cut out in other places (save $20 on an octo, etc) and go with what is comfortable in a BCD. BCDs are really hard to sell to someone whoes never used one, because you dont really fully appreciate the pluses and minuses of different types. Regulators have features that are pretty obvious to new divers as to their appeal so they are alot easier to talk about, and they cover a wider price range.
note also on computers: There are actually very few different computers on the market. All these scuba brands are either owned by the same company, or hire the same company to make their products. Ex: Oceanic and Aeris. Look at their websites and you'll see there is a striking resemblance. Equipment? Its identical! Computers all use the same algorithms, so its mostly format of how the information is presented and how you wear it that dictates what you go with. The software is all the same. (dont let someone tell you that brand A uses different or better software than brand B, in recreational diving its all the same, give or take extremely slight differences)