Among homebrewers, "have you gone all-grain?" seems like a rough analog to asking if you've lost your virginity.
"Oh yeah - I went all-grain years ago. I've been going all-grain so long I don't even know what extract is. It's just so much better - you've gotta try it..."
Sexual overtones aside, all-grain brewing really does have some distinct advantages over extract brewing, and I'm going to make a case for it (in case some of you readers are on the fence), but I'm also going to make a pitch for holding back just a little. Don't forget about extract brewing. Because while all-grain has its advantages, it has its downsides, too - and extract isn't without its virtues.
Go all-grain - but maybe don't go full all-grain.
The Case for AG
All-grain (AG, from now on) brewing has at least two clear, indisputable advantages over extract brewing: cost and control.
First, it's plainly cheaper. A grain bill of 15 pounds (pretty typical for 5-gallon batches) will run you about $30 or so, even less if you buy and store in bulk. For example, since I get grain by the 55-lb. sack, I'm usually paying well under a dollar a pound even for fairly expensive malts. An equivalent amount of extract for a 5-gallon batch will run you about $45-50, including any steeped specialty grains. That means that even the AG equipment costs you'll add ($100 or so will get you a nice cooler-based system) are rapidly recouped.
Second, it gives you a level of control that isn't there with an extract. Especially if you do your own milling, you can get a much more consistent product, fresher, and make lots of fun recipe/process decisions along the way - crush, mash temp and length, mash and first-wort hopping, and more. If you're using extracts, you're hoping the guys and gals at the extract factory were having a good day, and that your product wasn't oxidized all to hell and gone in the meantime.
Does it add time? Sure. But even that doesn't have to be a major consideration, as we've discussed before.
So why would I ever defend extract brewing?
The Worst Beer...
Lots of beer people are fond of saying that the "best beer is the one in your hand right now!" Now, I consider that to be trite nonsense that creates a kind of unacceptable beer-quality-relativism that I just can't stomach, but we'll have that debate another day.
What I can get behind, though, is the idea that the worst beer is the one you never get to drink, and that probably happened because you never brewed it.
In surveys of homebrewers (my own and the AHA's), the most common roadblock for homebrewers in relation to what limits their brewing isn't cost - it's time. And, say what you want, but extract brewing is FAST. Even faster than my efficiency-laden AG process. I clock in at 3:15 for an AG batch (which you gotta admit is still pretty damned fast!), but I can wrap an extract batch in under two hours, comfortably. If you can regularly find two hours, you can homebrew. If you can't ever find four then it doesn't matter how much cheaper or better-designed that beer would be, because you're never going to brew it.
And let's talk about quality. I believe (though I've never personally tested myself in a structured way) that, generally speaking, AG beers are better than extract beers, on average. Having said that, I'm not saying that extract beers are bad or undrinkable or that they can't in specific circumstances be as good or better than extract beers. They undoubtedly can.
I think the reason that we tend to assume AG beers are so much better is that, around the time we shift to AG brewing, we're better brewers. Our first batches range from awful to pretty good, and we rapidly improve (hopefully). We also change our methods around the same time, which could very well mean that we're conflating an increase in quality based on method with what might be an increase based on skill. When I brew extract, they're not quite as good as my AG batches, but they still do very well in competition and the people who drink them seem to enjoy them just as much.
For that reason, I always brew a couple of extract batches per year. First, it's easy to do, so why not, especially when I end up needing some extra batches around party season (3-4 Christmas/New Years events in three weeks)? Second, it lets me see how the product is these days - and extracts are better and more-specialized every year, much like our other ingredients. Last, it reminds me that there are a lot of paths to the top of the mountain, and so long as we do it right, there's no reason to think you're going to see a massive fall-off in quality.
Good brewing practices are generally good brewing practices, no matter the ingredients. With extract, though, I take just a little more care in two areas: style and mouthfeel.
First, I pick styles that don't require a ton of gravity points. "Extract flavor" may or may not actually exist, but I'm positive that if it does it's probably a good idea to minimize the amount of extract needed, so I shoot for lower-ABV beer styles. Not only that, but it can be tough to reach the right terminal gravity with extract beers that are swinging for the fences. Speaking of which...
Second, since extract tends to be slightly less-fermentable, you want to pay particular attention to mouthfeel and body. I do this two ways, and from both directions: I try to make the beer a bit lighter in body, but also a bit smoother and less "syrupy" in feel. One pound of a neutral honey (100% fermentable, baby!) will dry out the beer a touch (and feel free to use a non-neutral honey and add a fun flavor), and adding in a bit of flaked barley will soften the mouthfeel.
Brewing extract now and again is a great way to stay connected to your homebrewing origins. You might even find that a "new" extract beer becomes a favorite in your recipe book.
Keep it simple.