This is tough as I have very limited experience with either company's cabs. I love Mesa amps though and own an original WA Scout combo and am currently GASing hard for a TT800 but I've only used my 112 WA combo speaker and a PH410 to date and I didn't take to the 410 at all as imo it was a muddy mess.
I very briefly played a used Berg 210 in our local ma and pa one time and it was pretty awesome. Wish I knew which one it was. It was in the store for a very short time.
It seems to me that the Subway cabs are very very nice but also very very pricey (C$2,568 for the 2x10 and 1x15. That's a whole lotta jing if you ask me!

) plus they don't have the adjustable crossover like my WA does which kind of turns me off of them because imo for that kind of price it should have it hands down and it is a nice feature that I've used many times on the WA. I'd also like to see a totally defeatable tweeter. Really nice stuff but way expensive.
I have yet to run into a used one anywhere. The local area dealer won't stock any Mesa bass gear either which makes it even more frustrating. The one store guy told me that they aren't carrying Mesa anymore but he's such a bs artist to start with that I find it hard to believe. Plus there's still Mesa gear there 2 years later. Idk if the Berg cabs are price comparable or not.
Never played a Berg amp so no idea.
Would still love to try out the Subway cabs though as I've read so much good about them.
One other thought. I wonder if Mesa ever considered making a Subway 110? One or a pair of those for home use would be interesting.