This issue was resolved in the final versions of Emerald and is not an issue in Phoenix.

If you use the current version of the Emerald Viewer (no change in this respect from 1632) to log into Ocean Grid or another OpenSim grid at present, you'll notice that your avatar never rezzes and that you remain a gas cloud. It is optimised for SL rather than OpenSim. Hopefully this will change in a forthcoming version, as it has now been promised that this known bug will be fixed.

(This is also true of viewers based on the official LL Viewer 2.0 codebase, although using these with OpenSim can also cause substantial inventory damage, so they should not be used with OpenSim.)

Another small issue with Emerald is that its makers have chosen to always show their own splash screen rather than that of the grid that you are logging into. While Ocean Grid is not always online at night GMT+0/+1 for logistical reasons, this is a particular issue because you have to go to the website to see the online/offline status. While understandable that Emerald want to highlight their own brand, no other viewer does this, and it undermines the purpose of the splash screen in communicating news related to the specific grid. You'll notice that Emerald's splash screen includes both their own (Modular Systems) and Linden Labs' news, but of course none related to any other grid, despite the grid manager feature allowing logins to other grids.

Emerald also overrides the decision of the user to hide their online status from friends, by showing your settings to them. This undermines privacy and it's odd that this is not considered a mild contravention of LL's rules, as far as SL is concerned.

That said, aside from the temporary rezzing issue, Emerald is an excellent viewer and it's a shame not to be using it.