On price, Rocket.net starts lower at $30/mo against $34/mo for Pantheon. Rocket.net carries the higher rating overall, at 4.9/5, and Pantheon reports the better tracked uptime at 99.99%. Pantheon has been operating longer, since 2010.
If entry price is what decides it, start with Rocket.net. If rating and reliability matter more than the sticker price, Rocket.net has the edge. Either way, read the full profile before you buy — the trade-offs section on each page covers what the summary numbers leave out.