Their deployment is beautifully simple. The fact that they host several of my mini-apps makes me extremely grateful. But, the chances I will ever actually give them money are remote: their plans are scarily expensive. I'd rather spend 20 bucks a month on Slicehost and suffer the irritation of doing my own deployment.
I only started working with Rails about 6 months ago and was blown away by how easy it is to deploy apps. The whole set up literally took 5 minutes, and I didn't even know how to use git. I seriously considered their paid plan for a side project. But then I found myself reason "yea, I'm paying a premium for the elegant deployment flow and easy scalability. I'll use an extra dyno and turn it off at night to keep cost low. Maybe I use ferret first and then if thing picks up I set up an EC2 for Solr or Thinking Sphinx. Permanent storage? Well, I'll force my users to post picture somewhere else initially." So then I started looking at Linode and Slicehost and found that it's not that bad, especially with Passenger.
I'm a potential customer, I love their simple design and can't stop promoting Heroku to friends. I hope they succeed in solving those limitations and keep cost down in a reasonable range so that I can happily give them my money.
We have 10k/month coming in from our iPhone app and use Heroku + S3 for everything. It lets us focus on getting our product up to speed instead of system administration, period. If's only expensive if your time is worthless, or you really, really want to pay a sysadmin to take care of your server stuff.
Right now we're paying them $200/month and I smile every time I get the bill- it's one of my favorite expenses because of how much time it saves. When we get up to 5k, it's still a no-brainer. At 10k, it's time to start looking at Rackspace, but that's about the limit of things for us.
It works, it saves time, and it lets us focus on improving our product.
I'm still not quite convinced what need they fulfill, other than making it easy to deploy small/free apps. Sorry, that's just my impression. Anyone think differently? Please do correct this view if you think it's wrong.
That's quite a significant itch that they're scratching then. Look at the figures - 36,000 deployed apps speak for themselves, and the quality of the platform suggests that the big spike is still to come.
I tried to convince one customer to use Heroku, and we did for a while, but they ended up paying big $$ to RackSpace. Considering increased admin/engineering time, I have little doubt that they would have been better off paying $500/month to Heroku, rather than RackSpace.
Another customer wanted to use Heroku, but we ended up building our own system using multiple EC2s - again, long term the hosting costs will be much less, but the admin/engineering costs especially during development were a large expense.
For my own web portal project? I am using AppEngine (code in JRuby+datamapper+Sinara, but I am considering a rewrite in Java because of the superior tool support).
It is expensive, but i've found the dynos to be quite a bit more powerful than you'd expect. for instance, i'm getting the same req/sec from 1 dyno as i get from 3 passengers on REE 187. The CPU speed/rendering time is not as fast (getting 300ms on Heroku vs 80ms on Linode) - which is likely due to ec2 hardware.
We use Heroku a lot. It takes very little time to get a complete environment up for an application, and we're able to get production products out to test in the market faster than ever. We ported a Fortune 500 code base onto Heroku as an experiment, and it basically just ran, dependencies and all.
It's one of those products where until you actually use it, you question why it even exists. Once I used Heroku, I quickly realized the pain it was saving me from.
I have been using free acct for staging. I could not use service for deploy as we're using sphinx, plus will be processing incoming emails. The lack of total customization is the barrier -- but if that changes the overall fluidity of the service is incredibly appealing.
AFAIK there's nothing stopping you from using Amazon's SimpleDB, especially since Heroku is already running on EC2.
Also, given the "SQL Databases Don't Scale" by Adam I would be very surprised if they don't roll out a more "scalable" alternative to Postgres in the near future.
It's really easy to connect to hosted NOSQL environments though, if that's your cup of tea. AFAIK there are some solutions for most of them: MongoHQ, Couch.io and another one for Redis I can't recall.
You could also do it yourself. Basically anything that is also on EC2 shouldn't affect performance too bad.
It hasn't changed (yet?), but you can always put your NoSQL datastore on your own EC2 instances. Or you could use it with something like MongoHQ (http://mongohq.com).
