My answer's different depending on whether you're writing to get ranked in the search engines or purely to pre-sell the reader.

For the search engines, minimum of 500 words of quality content.

For pre-selling, it's going to vary massively depending on the product, the price point, and the market itself. I think it's really a question of writing enough to get the click/sale, by answering potential objections, explaining benefits etc.

If your article is too short... There is a good chance that many of your readers will be left hanging as you may not be able to cover all the information they needed on that particular product/service.

So I guess writing a 1000 word review is always a better option. If the visitor is genuinely interested in the product (Which is highly likely as they were looking for reviews) he/she wouldn't mind reading through a long article at all. You're simply giving them an excuse to justify their purchase

This is just my opinion though... I've never tried 500 word reviews on any of my sites. so I wouldn't know how well they work.

Edit: you could also add a link to your offer several times throughout your article so that your readers have a chance to go straight to the offer if they think they've read enough.

Hope this helps

Simplewriting

For SEO longer is better. For conversion longer doesn't mean better. I would try to add a video. A good video review generally increases my conversions.

It really sucks because Google likes 700-1000+ word articles, but the general population doesnt want to read that much.

For example, why do people read reviews on forums, or amazon? Because the reviews are short, to the point, from real people, and contain no fluff (most of them)

My solution to this is to create two posts. 1 for Google, and the real (short and sweet) review, for the reader.

Make sure your review has all of the elements of a good sales page.

I have alway gotten a significantly better response from articles and reviews that are 800 - 1200 words in length. They rank quicker and stick longer.

My days of doing 500 words articles and reviews are long gone.

I actually got 55 clickbank product reviews written. They are anywhere between 400-600 words per review, but they are in word document, so you can change whatever you need to. Make it your own...PM me if you are interested.

I think the review has to match the type of marketing you are doing. Is it a cold review or a review sent to someone you did some preselling too?

I've also found that typically 500 words onwards is the barest minimum for SEO. As to conversions, it depends on how you capture your reader and entertain them, along with
the cosmetics of clear call to actions and readability.

From experience writing articles and reviews, on average I also find that it's easier to pack in more information and value to your visitors at 700+ words onwards. At the same time, bear in mind that longer is not always better, since you still have to maintain your readers' attention and interest at all times for them to click through to your offer.

The trick is not to overdo it that people will start to skip what you are writing and at the same time, not too brief that it hurts the conversion rate.

Another tip, always write for people, not for google. Once you does that, everything else will fall into place.

It never hurts to write longer reviews. Really.

But that's if the article is relevant and it
engages the reader enough.

You want to "chunk" your review into parts
and leave sub-headlines. This will help the
readers with a "Scanning" style of reading.

You can also bullet your points.

Heck, just do a video if you have the real
product by your side.

Winston Tian

Until now I always used reviews with up to 500 words. Never more, unless I used PLRs.
The results were good, especially in Amazon niches. Much depend on the article itself, but try to build them with a friendly tone.

Include this:

1) Introduction
2) Pros
3) Cons
4) Personal thoughts
5) Why you bought it?

This works like crazy!

See you soon,
Alessandro Zamboni