Is the Hublot Big Bang 38mm a good everyday watch?

Yes for many owners. The quartz movement, sapphire crystal and 100m water resistance make it low-maintenance, though the gold case and diamonds need care.

Does it use a mechanical or quartz movement?

It is quartz. That means it keeps accurate time without winding, but it lacks the mechanical movement found in most watches in this class.

How does the 38mm size compare with the 42mm Big Bang?

The 38mm case sits noticeably smaller and lighter on the wrist. It suits people who find the 42mm Big Bang too bulky.

It is rated to 100m, so swimming and showering are fine. Avoid pressing the pushers or crown underwater, and have the seals checked over time.

Can the rubber strap be swapped?

Yes. Hublot's Big Bang straps are designed to be changed, and aftermarket leather or bracelet options exist, though original Hublot straps fit best.

How does it compare with a Rolex Datejust or Cartier Ballon Bleu?

The Hublot is bolder and sportier, with a diamond bezel and rubber strap. The Rolex and Cartier offer mechanical movements and stronger resale, but a more classic look.