Until recently i was hosting my site on the AWS free-tier micro instance. This is a fully self-managed stack and I didn't mind this, it's nice to keep my system administration skills fresh (or a little less rusty). I've gotten busy recently, and wanted an opportunity to look at both Acquia Dev Cloud and Pantheon for Drupal hosting. The following is far less of a comparison than it is a brief synopsis of my experience with each.
The one thing I will say up front is that the pricing page for each service has serious accessibility problems. This raised flags for me initially. Neither of the services UIs is horrible for accessibility (from a screen-reader user's perspective) and other than what is mentioned below I didn't run into anything that I simply could not do on either service.
*** Spoiler alert ***
I chose Pantheon.
*** End spoiler alert ***
Acquia Dev Cloud
I was impressed initially with Acquia dev cloud's sign-up, that there is a free 30 day trial, with no credit card information required. If you're choosing the $99 / month Developer Acquia network subscription this also includes $44 off your first month with Drupalize.me, making it only $1. Along with the Acquia network subscription you need to choose a hardware (AWS EC2) configuration, I chose the minimum option, at $65 / month.
The dashboard was a bit daunting at first, but that is to be expected with a new environment. One annoyance that I experience was that the link to switch from svn to git was completely inaccessible to me using the JAWS 13 screen-reader with Firefox 9, I had to have someone else find and click it for me.
The experience was pretty smooth other than the fact that I had troubles getting a database dump. I don't know if there is a dashboard option for this, if so it isn't accessible. I tried to use drush sql-dump, and it gave errors. After professional and timely support from Acquia I was informed that the problem was reproducible. A little while later support got back to me and told me that it was that my version of drush 7.x-4.5 does not support remote sql-dump. After doing a git checkout master in my drush directory the remote sql-dump worked without a problem.
It was a little harder to get signed up with Pantheon than Acquia Dev Cloud. Sign up was free, but it required an invitation code. I had a code from back in August, but the account had expired and I needed to request another. It came pretty quickly, but this could have been because I had a prior code, your milage may vary.
I tried... and tried... and tried... to import my site into Pantheon using their dashboard / UI, it failed... and failed... and failed. After filing a support ticket and getting, what I would again consider to be, a timely response I was told that the UI doesn't always get to the end where the import wizard is, and I was provided a direct URL for this (hint: append /configure to your site's dashboard URL). *** Note creating a new site or importing a site through the /configure URL will destroy all data. Things were relatively smooth after this, and getting the second (client) site imported was a snap... or maybe a few snaps. The database import on the second site didn't seem to work the first time around, but it was possible to do this after the fact using the dashboard and using drush.
I decided to make my site 'live', which requires paying for hosting. I was presented with only one option, $50 / month for the first 6 months, this is half off the standard Professional rate of $100 / month. This is a great discount, but I really wanted the $25 Personal rate. I was told by someone who could see the pricing page that this is greyed out, i.e. not currently available. I bit the bullet and launched at the Professional rate.
The final step of making the site live was setting up the domain name. I added the domain names zufelt.ca and www.zufelt.ca to the 'live' section of my site's dashboard, and it told me to set the CNAME for each to edge.live.getpantheon.com. This seemed a bit tricky to me as I didn't believe it to be possible to set a CNAME on zufelt.ca, but I tried. I logged into my DNS service provider, dyn.com, and tried to set a CNAME for zufelt.ca, it wasn't possible. Apparently some DNS service providers believe that you shouldn't allow CNAME records on a second-level domain. Reading http://help.getpantheon.com/pantheon/topics/configuring_dns
I foundthat Google Apps Hosting will also fail if you use a CNAME on your second-level domain, luckily the page also provides the IP address for edge.live.getpantheon.com, with a commitment that users will be notified if the address changes in the future. It also states that Pantheon will be offering static IPs and managed DNS as add-ons in the future.
In the end I chose to go with Pantheon, I prefer their per-site pricing, and the fact that the dashboard UI was a bit more streamlined. I have nothing negative to say about Acquia Dev Cloud, it just wasn't the right solution for me.