The replica Ballon Bleu 33708 worth buying is the 42mm steel automatic built on a Swiss-pattern 2892 or 2824 movement, with a correctly domed sapphire crystal, a concentric guilloche dial with the date at 3, and a blue cabochon seated inside a proper crown guard. Those are the criteria that separate a convincing 33708 from a generic lookalike: case geometry, dial texture, crown assembly, movement, crystal profile, and bracelet fit. Everything below is organized around those six points, followed by a buying checklist and a recommendation by use case.

What reference 33708 actually is

33708 is the case reference tied to the 42mm Ballon Bleu de Cartier in steel with an automatic movement. On the wrist that means a 42mm round case, a thick domed bezel, a short lug-to-lug span for its diameter, a fluted crown capped by a blue synthetic spinel, and a dial with concentric guilloche rings, Roman numerals, and a date window at 3 o'clock. Replica makers stamp 33708 on the caseback, but the stamp is not what makes a watch accurate. Dimensions and finishing do.

Two details to check before anything else: the caseback engraving should match the reference instead of a generic Ballon Bleu size stamp, and the crown should sit inside a curved guard that flows out of the case flank rather than floating next to it.

Case size and how the 42mm wears

The 42mm case is the reason people search this reference instead of the 36mm or 33mm versions. It reads large on paper but sits flatter than the diameter suggests because the lugs curve down and stay short. Most buyers with a wrist of about 6.75 inches or more find it comfortable for daily wear. Below that, the case overhangs and the watch looks borrowed.

Pros

  • Strong wrist presence without a chunky profile
  • Readable dial at a glance, including the date
  • Works with both the steel bracelet and a leather strap

Cons

  • Too much watch for wrists under roughly 6.5 inches
  • Polished bezel and case flanks show scratches fast
  • Thicker replica cases can sit taller than the original profile

Use case: this is a daily-wear size for medium and large wrists, and a dressier occasional piece for smaller ones. If your wrist is small, the honest move is to look at the 36mm case family instead of forcing the 42.

Dial and guilloche texture

The dial is where cheap replicas give themselves away. The original uses a stamped concentric pattern that shifts under light. On weak copies the rings are shallow, the pattern flattens at the edges, and the printed Roman numerals look thick and slightly muddy.

What good looks like

  • Even ring spacing from center to outer track, with no blur near the date window
  • Crisp printed numerals with sharp serifs and consistent ink weight
  • A date aperture that frames the number cleanly, without a white ring showing around it
  • Blued-steel-look hands with a clean sweep on the seconds hand

Ask for a macro photo of the dial center and a straight-on shot of the date window. Those two images tell you more than any spec sheet.

Crown and blue cabochon

The crown assembly is the signature of the Ballon Bleu line, so it deserves its own check. The fluting should be cut evenly, the guard should wrap the crown without touching it, and the cabochon should be a deep, slightly translucent blue with a domed top, not a flat plastic dot or a milky glass bead.

Pros of a well-built crown

  • Sits flush against the case with no gap that traps lint
  • Cabochon color matches the original's darker blue rather than a bright toy blue
  • Crown turns with light resistance instead of spinning loose

Cons to expect

  • Glued cabochons can loosen over years of wear
  • Replacement cabochons rarely match the original shade exactly

Movement options

Movement choice drives reliability more than any cosmetic detail, and it is the clearest way the market splits into tiers. Several factories build Ballon Bleu replicas and quality changes batch to batch, so judge the individual watch you are shown, not the name attached to it.

Swiss ETA 2892 pattern

A thin Swiss automatic with a central date, well suited to a dress watch case because it keeps the profile low.

Pros

  • Reliable timekeeping and easy service by any competent watchmaker
  • Thin enough that the case does not sit tall on the wrist
  • Smooth winding feel and quiet rotor

Cons

  • Higher cost than clone movements
  • Availability depends on the seller's current stock

Use case: best pick for someone who wears the watch several days a week and wants it serviced later rather than replaced.

Asian automatic, 2824 or 2892 pattern

The middle tier and the most common option in a 33708 case.

Pros

  • Solid day-to-day reliability when the movement is properly regulated
  • Cheaper to replace than to repair
  • Parts are widely available

Cons

  • Timekeeping varies between individual units
  • Louder rotor and rougher winding than a Swiss base

Use case: the sensible choice for a first replica or a watch that rotates with others in a collection.

Quartz

Pros

  • Accurate, low maintenance, and thin

Cons

  • Sweeping seconds hand is missing, which is visible up close
  • No winding feel, and the caseback often sits differently

Use case: only if you want a low-effort beater and accept the seconds-hand tell.

Crystal, caseback, and bracelet

The crystal should be sapphire with a dome that distorts the dial edge slightly when viewed at an angle. Flat mineral glass gives a hard, thin reflection that looks wrong in photos. On the back, check the engraving depth and the reference stamp. On the bracelet, look for solid links, a signed clasp, and no rattling at the end links. A leather strap is more forgiving of small case flaws, which is why many buyers swap immediately.

Buying checklist

  1. Confirm the case measures 42mm across, excluding the crown.
  2. Request a macro shot of the dial center and the date window.
  3. Ask for a close-up of the cabochon in daylight, not studio light.
  4. Confirm the movement type and whether it has been regulated.
  5. Check lug-to-lug against your wrist before you commit.
  6. Ask about the return window and warranty terms in writing.

Which one to buy

If you wear one watch most days, take the 42mm with a Swiss-pattern automatic and a well-cut guilloche dial. If this is one of several watches in rotation, the Asian automatic tier delivers the same look for less and is easier to replace. If your wrist is under about 6.5 inches, step down to a smaller Ballon Bleu case rather than buying the 42 and hoping it works.