Imperial Guard Sabre Defence Platforms – Are they worth it?

I was recently on the Forge World site, looking at the Cadian Hostile Environment Conversion Sets and found myself completely drawn in by the Imperial Guard Sabre Defence Platforms. You have to admit they look pretty sweet:





I don’t know how feasible these would be in a game, but if you’re playing something scenario based I think they would be a real visual treat protecting an emplacement. The question I have is who has used them, are they useful and worth taking and which of the variants are the most sucessful on the table?
Any information or suggestions on their performance would be great.
Cheers