My extract beers are good, I think better than most commercial beers that I buy. Extract takes less time, less equipment and seems to produce great quality beers. Why do people do full grain?
All grain is cheaper (in the not-so-long run), you get way more flexibility on your grain bill and mash, I'd argue it's more fun, and it's really easy to do.
After ten years of kits and extracts, I finally went all-grain 6 weeks ago. It is so much fun! If you enjoy what you're doing now, I'd say give it a try because there is so much more to enjoy. I've brewed on 5 of the last 6 Saturdays, and had a great time each time.
I only spent about $150 on extra equipment, and that includes a grain mill. I can buy my grain uncrushed in bulk and save a lot. I can now brew a batch of beer for about $14 of ingredients.
It doesn't get much better than this.
Personally I think our all-grain batches taste better. This might be due to the better grains we are using, or the fact that we are better brewers now.
I've had some tremendous partial mash beers. If you have good quality extract and supplement with some specialty grains, I think you can get very high quality results.
I think the biggest downside is that you have less control over the final beer and thus are more limited in what you make.
So I would say stick with extract until the idea of doing a full mash sounds appealing.
I agree with PVM and Jeff about the costs and time issues. I also agree about the fun factor. I find it to be a very relaxing and enjoyable morning when I brew. I brew outside on the patio under my deck. So I tend to do most of my brewing in the spring and fall. I work around the weather as needed. A morning spent brewing reminds me a lot of a morning at a tailgate. There's a moderate amount of activity to hold your attention and when you have free moments you can kick back with a beer and enjoy the fresh air (and smell of beer brewing).
I agree with mike. I think all grain is even a step up from extract.
And Tim's right - it's for the person who wants more control of the process/outcome. I have the choice of Munich or Vienna or biscuit or any other mashed grain in any proportion I like. It's hard to impossible to do with extract + specialty grains.
My advice: Try partial mash recipes to get the feel for it. The rest is pretty easy: just scale up. Or don't. You'll at least have a great feel for what the process is.
On the other hand, what's simpler than extract to get a really tasty beer? You're right, it's better than many store-bought beers.
My primary motivation was to have more choices in what contributes to the flavor of my beer. I only brewed two extract beers before I started all-grain, because I found the extract choices extremely limiting. I've taught several friends to brew since, and have never started with extract. None of them regret it, and none have had any interest in reducing the brew time for its own sake.
My secondary motivation (related to the first) was to be "closer" to the process of brewing. I took an interest in home brewing because I wanted to produce the kinds of beer that I want to drink. I have more involvement in what I'm brewing when I use "raw" ingredients. (Yes, I realize that I'll have even more control in this respect when I begin making my own malts, or even growing my own ingredients.)
As someone who's also made very good extract beers, I've experienced a notably better taste, quality and freshness with all-grain. But even more than that, it's given me a whole lot more freedom to experiment. Of course you can experiment with extract, but you can only go so far. I was nervous, too, but as you can read on this list, it's WAY more fun...