Is the Marathon worth it?

It's an entirely different experience. Those last few miles are quite a bit different from any feeling you'll ever have doing the shorter distances.

This doesn't make it better or worse, just different. Sometimes the boost in mileage and focus can be helpful. Sometimes going all-in on a marathon can take up a big chunk of your year. Some like it and some don't.

I don't get the half marathon thing. Why race half of something? Why do a race that is 13.1 miles? Go the full marathon or do 10 milers! ;)

the last hour of a marathon is truly a dig-deep experience - unlike any other race. if you are at your limit, you look into the pit for a long, long time. You find out what you got.

That said, I am done with them - after 5. I don't think they are good for me, mentally or physically.

The marathon is great because it rewards the wise and punishes the ignorant like no other race. You can go to your local 5k/10k without much specific training, go out too fast and struggle to keep from dropping 10-15 sec a mile the last few and still run a half decent time. Do the same thing for a marathon and you will be a runner zombie for the last 6-8 miles, shedding minutes off your time and finishing alongside runners who you would usually beat by minutes at shorter races.

Totally worth it! If you run a half marathon or a shorter race and you have a bad day and run 5 secs/mile slower than your goal, you probably feel it was a total waste. Not only the race itself but after a 13.1M race effort you're not back to quality training for another week or two + you likely "lost" a week prior to the race to sharpening or mini-tapering rather than real quality workouts.

I don't have that feeling after a marathon even though the damage is far greater. In my last two marathons I missed my goal by 11 and 5 minutes, respectively. One due to race-day conditions, the other due to my own race prep + bad pacing decisions on the course. And yet, I felt great afterwards. Sure I was annoyed with my times but I didn't think it was a waste. There's a sense of satisfaction you don't get from finishing a half. And the buzz at a marathon finish, whether it's a mega-race or just a small hometown race is special. People come out in force to cheer on their friends and family at a marathon, even the people finishing hours behind you. It's an event. Doesn't compare.

Whether you want to focus your training on the marathon for a whole season or just throw in a few extra long runs to be able to complete it, I think every road runner should at least try it. Gives you a new perspective on your 5K or 10K. A couple of my team mates did just one and declared they'd never do another, but they both set big new 10K PRs the following season. According to one of them, because his mental approach to training had completely changed.

With the entry fees they charge nowadays, there's no reason for non-elites to participate. Read, ZERO ROI.