The pvr stalker was partially down for me too yesterday but seems ok now.
The service is still free through the iVue addon and until they shut down all avenues of "freeness" we're not going to see an improvement in the service.
Its a toss-up between which is the better way to view the service, as in which draw back bothers you least. Ivue does not have all the channels and sky one does not work and on the stalker pvr you get audio hiccups.
For anyone else suffering that audio issue on pvr stalker I got a response from a dev on the github repo page and it has been noticed and a fix is in the process.