In some places of my copy I do a little comparison of what they will get with my product vs. the lower quality competition. I don't mention brand names, but the qualities of a lower quality product and the results.

Is that something you do on a fairly regular basis, no matter the client/product?

The way I see it, comparing products is a solution to a problem—prospective customers are shopping around. However, your approach comes across a bit like, "when all you have is a hammer, every problem looks like a nail." In other words, other solutions exist, and they might be more effective.

For example, if the product has specifically been designed to be the Anti-X and it's a significant part of its brand identity, a comparison might be the best solution. e.g. A social network that doesn't sell your data, unlike Facebook. In this instance, you'd be using the reader's fear and the public backlash against Facebook to your advantage. Plus your target customer is likely to be anti-Facebook, so there's little chance of you reminding them of its existence and them leaving your page, and there's a good change this will demonstrate shared values.

But if this isn't the case, I'd fear the aforementioned reminder of the other product, especially if it's better known and trusted. e.g. You could say, "Unlike the iPhone, our product can sustain falls from over 50 ft and is waterproof to 10ft"... but I've had an iPhone before, so at least I know its flaws. Plus everyone has one, so it's got to be doing something right, right?

The only times I've seen comparisons and thought they made sense is on pages for web site builders, CMS, and similar products, and in advertising in which one big brand is comparing itself to another (e.g. Pepsi vs. Coke, one big supermarket chain vs. another).

So, personally, unless there was a strong strategy behind it (or if people are asking, "How is this better than...?" or "How does this compare to...?"), I'd just sell the value and benefits of my product and not mention competitors.