Ben went a little apeshit and mini-reviewed 15 different weather apps, and I love him for it. Like Ben, I settled on WeatherSnitch a while ago (February 2010), after (buying and) downloading nearly every decent-looking weather app that's come out since the iPhone was originally launched. (Even today I have a "Weather" folder that holds the last 12 apps I've put on my phone. Ladies.)
When I noticed that the latest version of WeatherSnitch was injecting ads into the app, my reaction was similar to Ben's; not only do I just refuse to have ads in my weather apps (or any app for that matter), but it really burns me up that I paid for this app, and now suddenly it's free and forces ads on me.
To be fair to the developers, they did say the following in the latest release notes (and so maybe we'll be able to turn the ads off in a future update): "We know this update might bug some of you, but it's necessary as we prepare to release the next version (long overdue, we know). These changes will be temporary…" (Emphasis mine.)
In light of this ad nonsense I ended up falling back on My-Cast (and am quite enjoying Fahrenheit too), which, coincidentally, is the app Ben ended up coming around to as well. It was an automatic switch for me, because My-Cast was my daily driver before WeatherSnitch came along.
Of course there were reasons I abandoned My-Cast in favor of WeatherSnitch, which reasons still persist, including: 1) the name (it looks terrible under the icon; WeatherSnitch simply says "Weather," which is perfect); 2) the icon (seriously, tell me it doesn't look like it belongs on a box of Jimmy Dean sausages); and 3) the fact that you can't force it to update its weather data (no matter what I do, the app updates for me only at 1:53, 2:53, 3:53, etc.).
See also Marco Arment's thoughts on weather apps, which mostly are in line with my own with respect to what I want in a weather app. That said, neither Ben nor Marco mentions a desire for a "feels like" metric. I prefer this kind of approximation to just the simple temperature, because it makes temperature less relative. For example, 60° in Florida (where I grew up) feels a lot different than 60° in downtown San Jose (not least because of the oppressive wind here), and despite all the years I've lived in California, I still have to do some mental math every time I'm given an absolute temperature.
(As a quick aside, Ben's screenshot of Weather+ cracked me up. The app--a weather app--wastes a fifth of the precious screen real estate on the time.)