TS Optics 1.0 Binoviewers (no barlow needed for newts) - will coma corrector work? Is it needed?

[Ships and Stars]

Hi all, I am starting off my eyepiece/binoviewer collection and am very close to buying a somewhat pricey TS Optics 1.0 Binoviewer that (supposedly) due to its unique design does NOT require a barlow etc to achieve focus on fast dobs (20" Stargate f/4). It sounds perfect for DSOs because no appreciable dimming should occur, but can't find any reviews expect a CN review that claims a number of issues all around - a definite deal-breaker!

Link to sales site:

https://www.teleskop-express.de/shop/product_info.php/language/en/info/p10297_TS-Optics-Binoviewer-1-0-magnification-zero-optical-path-and-erect-image.html

I am also looking at an Explore Scientific HR coma corrector as a lower cost alternative to the Paracorr 2. 

Does anyone have experience with this specific binoviewer, is it THAT bad as the CN review clamined? Would anyone know - is a coma corrector compatible with the TS 1.0 binoviewer? 

I hear coma correctors may not work/be needed with traditional BV setups due to use of 1.3/1.6/2x barlows etc, but the TS 1.0 seems to be uncharted territory.

After I win the lottery, I shall get a Siebert Elite 45 2" BV, haha! ?

Any info greatly appreciated!

Clear skies all.