As good as Hotspot is, it still needs tuning. The simple truth is there isn't a "one size fits all" solution for GC, it really depends on what you're doing and how the performance characteristics fit in to it.
To clarify my down-voted comment a bit: I think part of the problem is that GC tuning has become kind of a black art. It's hard to find documentation and advice to get good results. Tuning services like MySQL, Apache, Nginx is pretty straightforward; there's documentation, guides, tools and plenty of clear ways to monitor it. In my search for Ruby VM tuning, I've found only very technical guides or blog posts that involve a lot of steps, and are not focused on real-world experience.
That being said, I'd like to try this service, the guys behind it seem to really know what they are doing.
Thanks for the heads up. One of the biggest goals driving this service is the fact that an incredible amount of awesome is going into Ruby 2 releases. Yet it's not straightforward for everyone to keep up to date with developments and because GC is work in progress, it's going to be difficult to run apps with optimal settings, especially with upgrade paths etc. We worked on this to primarily bridge that gap.
