I admit I have a soft spot for Genta Retrogrades and tantalum. These are both. The price would be my only problem... ouch! (Incidentally, if you guys at Genta ever read this, could you PLEASE do something about your crowns? They just don't work too well on the more sporty models. They are OK on smaller women's Mickey Mouse model but these larger more masculine Arenas just don't look the part. Thanks.)
Tantalum is becoming a real option and alternative for those who want the "heft" of gold yet don't like its yellow color. AP was first with the Royal Oak to use this precious metal. Lately Panerai and Hublot have also added this metal to some of their limited series models. The Panerai Tantalum had a full case and the Big-Bang only the bezel. Tantalum has several interesting properties. It is hypoallergenic, almost as heavy as gold (yet much harder) and is as resistant as glass against corrosion and acids. Tantalum is a very dark metal that gets purplish color over time and feels warm to the touch, contrary to steel that feels cold.
Let's hope that the backs are not sapphire. The movement is certainly no beauty, effective but no beauty. I would rather have a solid case back, more depth rating and a nice engraving rather that seeing the back of an ETA or Valjoux 7750.