Thank you mwillems! That's great information.
If it's not too much trouble can I ask you what the control quirks are? I don't have many requirements and if it's easy (for the wife also) may make it a better choice for me.
My best advice is to try it and see. There are a bunch of ins and outs, and it's hard for me to know what quirks are important to you. One example I've observed when using method 2): when you send an album to the "client" DLNA renderer, the album will play out as expected if left alone. If you try to stop playback on the renderer itself (rather than using Gizmo/the server), it will skip to the next track instead of stopping. So to summarize, if you play an album to "TV PC" using Gizmo, if you try to stop playback on "TV PC" itself (instead of stopping on Gizmo), it will just skip to the next track instead of stopping. So you have to remember how you started playback to know how to stop, etc. There are other things like that, but testing it is the best way to find out which quirks will bother you and which will not.
When you use method one, there are no quirks, it works exactly as though you were playing the files in media center, etc. You have to remember how to change libraries/servers in Gizmo, but once you've put the access codes in, they're on the same list as zones are, just at the bottom, so it's not really that much more work (there's just extra work on the front end). As long as the computers have descriptive names, it's been relatively easy for my family members to figure it out. Basically if they're comfortable selecting zones to playback, this isn't that much different in Gizmo once you have it setup.
Is the "rendered" function a massive CPU hit? The Server in this case has 4 cores dedicated to it, the "TV PC" in this case is actually a touchscreen jukebox with a 4 core intel PC but only 2.X ghz (Dell All In One 2043 if i'm not mistaken)
Just wonder how crushing those functions will be. They're all on wired gigabit LAN so that sohuldn't be an issue
If configured correctly there should be virtually no additional CPU load. MC just sends the file as is to another MC instance (to my knowledge), unless you tell it otherwise.