Audeze LCD3 vs LCD-X

Hi there. I was wondering if people could share their experiences with the Audeze LCD3 headphones compared to the cheaper LCD-X.

I demoed the LCD-X and I'm considering purchasing them to replace my Sennheiser HD800 headphones.

My local hi-if store owner has advised that the upgrade to the LCD3 wont be worth it, as my source is 'only' a Naim DAC V-1. However, he didn't have the 3s in stock to compare.

The main reason I prefer the Audeze to the Sennheiser is the extra bass. I understand that the Naim may also contribute to this, but afaik it would cost a considerable amount to upgrade my source and I don't particularly want to do this.

Finally, I understand Audeze may soon be updating their product range, so it could be worth holding on.

Any advice much appreciated.