I train at home and have pretty much everything I need there.
I decided to go this way for the following reasons:
1. Cost - Once the initial purchases are out of the way I save a lot of money compared to never ending gym fees.
2. Convenience - I just need to walk out to the garage and I can train. Don't need to drive 15 minutes each way to a commercial gym. I'd prefer to spend that extra time with my family, plus there's more chance of me piking it and thinking I cbf organising myself to go there.
3. Dickhead Avoidance - I've been to a few gyms on my work travels and have seen enough wankers that like to stare at others and smile and whisper stupidities. It's better to train with a total focus on your workout and no idiotic distractions.
The only negative I can see of home gym training is the absence of top notch advice/coaching. You're not guaranteed to get that at most gyms anyway, but if you can find a gym where you do get specialised coaching attention then I would recommend going there, even as a supplement to a home gym set up. I've had a few sessions at Shire Speed & Strength, and the coach there is excellent, really knows his stuff. If it wasn't so damn far from me I'd continue going at least once a week.
EDIT - The other negative is the absence of eye candy, however I see enough of that during the day to keep me happy.