Gen 1s should not be on sale new any more, or at least must be old stock.

IMO you should buy gen 2, whatever the discount that may be offered on gen 1.

Ok thankyou for the reply, she also said I should be looking to buy a beam rather than an arc, as I have 4 corners in my front room, do you agree with this?

Well, 4 corners doesn't seem an unusual spec for a room. That comment doesn't make any sense to me!

No nor me, I think she means if I had a massive room I should be looking at an Arc but if I have a normal standard size room I should very looking at a beam, do you agree with this?

I think a room can be too big for a Beam, but I am not sure a room can be too small for an Arc. 

Are you planning to get surround speakers and / or a Sub?

What are the dimensions of the room?

The Arc has upward firing speakers, which should make for a better rendering of Dolby Atmos, if your TV can do Atmos. That really requires a flat ceiling, but that would not be an unusual spec for a room.

The size of the room is 5.4 metres by 3.5 metres and the height of the ceiling is 2.3 metres, regarding the TV its a Samsung QE75Q60AAUXXU It's quite new but not sure about Atmos as I have never heard of it, I am new to all this and want to build it all up, regarding the surround sound speakers yes I am I have one already and going to get the 2nd when I get the beam or Arc

Your room is slightly bigger than the room in which I use my Arc.  Either Beam gen 2 or Arc would be suitable. It's really down to whether you think the better sound is worth the extra cost.

A newish Samsung TV should do Atmos but I cannot promise  

Atmos is a form of spacial surround sound.  I suggest you Google it.

I would go for the Arc, but it is easy to spend other people's money. 

Our space is a bit more open than what you describe and while a Beam sounded decent the Arc sounds a lot better in the same place.

We have a Beam (no sub or surrounds) in a 15’ x 14’ room and it is doing just fine for general TV watching, not horrible for movies but the Arc, Sub and surrounds in the media room sound a lot better.

If the money is there you won’t regret the Arc.

I recently bought a Samsung TV and wanted to ensure that it would output Atmos to my Sonos Arc. The key feature you are looking for on the TV is “eARC” - which stands for enhanced Audio Return Channel. “ARC” has been around for many years but you need the ‘enhanced’ version on your TV to support the additional complexities in Atmos sound (more channels, detail, etc). Reasonably good overview of ARC: 

eARC is not in fact essential for Atmos, only for lossless Atmos.  HDMI-ARC can carry Atmos over DD+, which is what streaming services such as Netflix use.

eARC is nevertheless a feature worth having in a new TV as a bit of 'future proofing'.