Side by side

Formex Reef GMTvsSeiko 5 Sports SKX series

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

Reef GMT
FormexReef GMT
MSRP $2,235
5 Sports SKX series
Seiko5 Sports SKX series
MSRP $495
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.

Seiko 5 Sports SKX series

The Seiko 5 Sports SKX series is widely praised as an excellent gateway watch, offering great value with a solid build and powerful lume. Owners widely report that the NH36 movement's accuracy is a "luck of the draw," with official specs allowing up to +/-40 seconds per day, though many experience +/-5 to 10 seconds. Some owners note the lack of a screw-down crown and 100m water resistance, while others highlight its ISO 6425 compliance, 200m water resistance, and screw-down crown as superior tool watch features. Some owners find the original SKX models heavier and bulkier than newer lines, while others praise its iconic, tough, and rugged dive watch design and proven durability. On balance, owners and reviewers rate the Seiko 5 Sports SKX series highly for its iconic, durable dive watch design and strong value proposition.

At a glance

10 of 29 specs differ
Diameter
Reef GMT42mm
5 Sports SKX series42.5mm
Power Reserve
Reef GMT56h
5 Sports SKX series41h
Water Resistance
Reef GMT300m
5 Sports SKX series100m
MSRP
Reef GMT$2,235
5 Sports SKX series$495

Full specifications

Case

4 specs
Diameter
42mm
42.5mm
Thickness
11.4mm
13.6mm
Lug-to-Lug
47mm
46mm
Water Resistance
300m
100m

Crystal & Dial

2 specs
Crystal
Sapphire
Hardlex
Lume
Super-LumiNova
LumiBrite on hands and index(es)

Movement

3 specs
Caliber
Sellita SW330-2
4R34
Power Reserve
56h
41h
Jewels
25
24

Pricing

1 specs
MSRP
$2,235
$495
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