Also the best place to clip it?

Maybe this is a personal preference decision. I was looking at the GME610G as they are Aust made, but there weren't any on the market when I needed one. I went with the Rescue Me PLB. Both have 7 year battery life. The Rescue Me is smaller and lighter, but not inherently buoyant. I use it with its buoyant foam cover.
Where to locate it maybe depends on your use or not of a PFD. I always use mine if solo/offshore with the PLB attached or attached and in a deck vest chest bag.
I don't like how some satellite communicators are being advertised as PLBs. I also carry a Garmin InReach mini, however these, Spot locators etc are monitored by international commercial services, not directly by AMSA. I've seen Spot locators triggered accidentally in central Australia and it was 6+ hours before any local services were informed. Not a delay you want if you're in the water.

DrogueOne said..
Interesting that you need to keep it out of the water with antenna extended to maximise connectivity.

They are all subject to this - nothing to do with any particular design, just the laws of physics and the fact that the VHF signal won't propagate through water.
Amongst all the other things to consider, you need to figure out how you to keep your PLB out of the water with antenna vertical as you gradually become exhausted and unconscious.
My Crewsaver Ergofit PFD has a sort of sleeve over the bladder which will hold the ACR ResQLink PLB nice and snugly out of the water with the antenna vertical while I become incapable of holding my arms up, my body temperature drops, and well you know the next bit ...............!!
That way there's a good chance the SAR will return with a body.

Cheers, Graeme

Thanks guys once again for all the good info. Encouraging to note that the three main contenders are Australian, American and British rather than Chinese although I'm sure that plenty of the components esp in the OZ one are made in China.

Went with the ACR 400 as in the end I couldn't really decide definitively in favour of one or the other and it's on sale at BCF although irritatingly it doesn't quite fit whilst attached to the manual blow-up piece in my Marlin PFD without a little bit of a PFD flap non closure issue.
Maybe I should have got the Rescue Me which is truly tiny and probably still has a lesser circumference when the supplied flotation jacket is about it. Anyway the ACR might remain right side up if deployed on the life jacket inflation mouthpiece so that's where it's is for the moment rather than on a belt clip which is also supplied.