The open backs (Clear, Utopia) are very well tuned with particularly good dynamics and impact. Soundstage is smaller than something like a HD800S or Arya but sometimes you want that. The HD800S soundstage can be big to the point where it feels unnatural and lacks impact, the Clear feels more natural and has much better punch.

Soundstage while smaller than headphones with the very largest soundstage is still larger than the Sennheiser HD6X0 series. The OG Clear as /u/lh-95 says is a direct upgrade to the HD6XX, it's a very similar sound signature, but more technical, more detailed, more "clear", like the veil has been lifted. So if you like the HD6XX, you'd probably like the OG Clear.

Build quality is poor (the headband is a particular point of failure and is creaky even if it hasn't failed) and failure rates (both headband and driver) on certain models are very high. Replacement parts are ridiculously expensive, this includes the pads which are $200 MSRP. If you are in the US though there are some places selling Focal pads at lower prices, around $100. Third party pads are available but sound different.

It depends I think as well what you can pick them up for. The A$999 Addicted to Audio (Australia) price on the OG Clear is equivalent to US$600 ex-tax which is an insanely low price for the OG Clear.

Many prefer the OG Clear to the Clear MG, which seems overly dark. I haven't heard the latter, but I suspect I'd prefer the OG Clear which is a great headphone, if not perfect (but nothing is).