I know, I know. Google's indexing Flash and Flash developers can rejoice now that their content is SEO-friendly. Sorry - I don't buy it for a second. Flash content is fundamentally different from HTML on webpage URLs, and being able to parse links in the Flash code and text snippets does not make Flash search-engine friendly. I think it's great that Google's digging deeper into Flash, but I don't believe web developers should be any less wary than they've been in the past about Flash-based websites or Flash-embedded content.

And guess what - I used to be a Flash developer (prior to founding SEOmoz). I still build graphics and wireframes and content (like this demo I quickly made for SEOmoz's PRO content) entirely in Flash. I'm not a hardcore Flash junkie or an actionscript developer anymore, but I can say with confidence that Flash ≠ a smart SEO strategy.

Some reasons why include:

1. Different Content is NOT on Different URLs
   This is the same problem you encounter with AJAX-based pages. You could have unique frames, movies within movies, etc. that appear to be completely unique portions of the Flash site, yet there's no way to link to these individual elements (unless the Flash developer is specifically building for this scenario - and even then, there's almost always some portions that are missed).
2. The Breakdown of Text
   Google can index the output files in the SWF to see words and phrases, but in Flash, a lot of your text isn't in nice clean <h1> or <p> tags, it's jumbled up into half phrases for graphical effects and will often be outputted in the incorrect order. Worse still are text effects that often require "breaking" words apart into individual letters to animate them - I'm guessing search engines aren't yet smart enough to play Scrabble with Flash output.
3. Flash Gets Embedded
   A lot of Flash content is only linked-to by other Flash content wrapped inside shell Flash pages. This line of links, where no other internal or external URLs are referencing the interior content, means some very low PageRank/link juice documents. Even if they manage to stay in the main index, they probably won't rank for anything.
4. Testing Crawlability with Hope
   That's what you're doing with Flash content for SEO - hoping. Google's Flash-crawling technology is proprietary, and while we all know and can test what search engines see from a content and link perspective in HTML, there's no "test my site's Flash file crawlability" feature that I'm aware of, leaving us very much in the dark about exactly how the engine's going to parse your material.
5. Flash Doesn't Earn External Links Like HTML
   For whatever reason, etiquette on the web simply doesn't lend itself to Flash media earning link love. An all-Flash site might get a large number of links to the homepage, but interior pages almost always suffer. For embeddable Flash content, it's the HTML host page earning those links when they do come. As a simple example, imagine a blog post or news article in HTML - those who enjoy it might copy and paste a few quotes into their own pages and link over, yet this rarely ever happens with Flash text (which can be hard to copy and paste unless the designer builds it properly) and even still isn't common practice among the "linkerati."
6. SEO Basics Are Often Missing
   Anchor text, headlines, bold/strong text, img alt tags, and even title tags are not simple elements to properly include in Flash, and 9 times out of 10, the designer won't build them in properly. Developing Flash with SEO in mind is not just more difficult than doing it in HTML, it's not part of the cultural lexicon of the Flash-development world.
7. A Lot of Flash Isn't Even Crawlable
   Google said they don't execute external javascript calls (which many Flash-based sites use) or index the content from external files called by Flash (which, again, a lot of Flash sites rely on). These limitations could severely impact what a visitor can see vs. what Googlebot can index.

Of course, it is nice to see some Flash content ranking at Google (like for the query "break apart flash letters," which illustrates point #2 above quite nicely). Just don't let a Flash developer who just found out about Google's new ability to crawl their work talk you into doing anything rash.

I love Flash - I still work in it and I think that a lot of great sites and applications have used it well. But,  trusting Flash content to get good SEO results is like trusting a Seattle summer wedding to be rain-free. It could happen, but no one would call it a wise bet. If you're seeking to make Flash as accessible and SEO-friendly as possible, that's a noble philosophy (and Jon Hochman's How to SEO Flash is quite a good start), but making it your primary content delivery system on the web is a recipe for disaster.

p.s. For more on the subject, see Ian Lurie's post - Google Indexing Flash, Don't Party Just Yet and Flash's New SEO is Overhyped from Ickydime.