Side by side

Formex Reef GMTvsGrand Seiko SBGA427

The numbers, the dial colors, the calibers — laid out so you can stop flipping between tabs.

Reef GMT
FormexReef GMT
MSRP $2,235
SBGA427
Grand SeikoSBGA427
MSRP $5,800
What people say

Owners + reviewers, side by side

Synthesized for each watch independently from owner discussions, enthusiast forums, written reviews, and video reviewers.

Formex Reef GMT

The Formex Reef GMT is widely praised for its unique porthole case shape, COSC-certified Sellita SW330-2 movement with good finishing, and comfortable quick-release bracelet with on-the-fly micro-adjustment. Reviewers note its robust construction, impressive specifications, and strong value proposition, with a slim 11.4mm profile accommodating 300m water resistance and an exhibition caseback. However, owners widely report the 53mm lug-to-lug span with male endlinks makes it too large for smaller wrists. Some find the bezel action stiff and potentially slippery, and a reviewer desired sharper finishing and edges, deeming the aesthetic too modernist. The GMT variant sacrifices a timing bezel unless swapped, and one owner notes sharp edges on the crown and crown guard. Overall, owners and reviewers highly rate the Formex Reef GMT for its exceptional value and well-executed features, particularly its bracelet system and COSC-certified movement.

From video reviewers

The watch features a COSC-certified SW330-2 GMT movement, which is visible through a sapphire crystal display case back and beautifully decorated. The watch's water-resistance of up to 300m/1000ft is a notable feature. The 42mm diameter may be too large for smaller wrists.

Grand Seiko SBGA427

Grand Seiko SBGA427 owners widely praise its extensive Zaratsu polishing and the "hall of mirrors" effect created by its diamond-cut indexes, complemented by a subtle, reeded dial and a striking green seconds hand. The 39mm case is noted for its comfortable, tapered bracelet, and the 9R65 Spring Drive movement is visible through the caseback. Some owners report the highly polished Zaratsu finish is prone to scuffs and scratches, with one mentioning a scratch near 1 o'clock. The Grand Seiko SBGA427 sold for $3750. Overall, owners rate the Grand Seiko SBGA427 highly for its exceptional finishing and the unique visual appeal of its dial and indexes.

At a glance

12 of 29 specs differ
Diameter
Reef GMT42mm
SBGA42739mm
Power Reserve
Reef GMT56h
SBGA42772h
Water Resistance
Reef GMT300m
SBGA427100m
MSRP
Reef GMT$2,235
SBGA427$5,800

Full specifications

Case

6 specs
Category
GMT
Dress
Diameter
42mm
39mm
Thickness
11.4mm
12.3mm
Lug-to-Lug
47mm
46.8mm
Lug Width
22mm
19mm
Water Resistance
300m
100m

Crystal & Dial

2 specs
AR Coating
Inner
Yes
Lume
Super-LumiNova
None

Movement

3 specs
Caliber
Sellita SW330-2
9R65
Type
Automatic
Spring Drive
Power Reserve
56h
72h

Pricing

1 specs
MSRP
$2,235
$5,800
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