Side by side

Grand Seiko SBGR321vsLongines PrimaLuna

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

SBGR321
Grand SeikoSBGR321
MSRP $5,200
PrimaLuna
LonginesPrimaLuna
MSRP $2,950

At a glance

19 of 29 specs differ
Diameter
SBGR32140mm
PrimaLuna34mm
Power Reserve
SBGR32172h
PrimaLuna72h
Water Resistance
SBGR321100m
PrimaLuna30m
MSRP
SBGR321$5,200
PrimaLuna$2,950

Full specifications

Case

7 specs
Diameter
40mm
34mm
Thickness
13mm
11.6mm
Lug-to-Lug
46.6mm
41mm
Lug Width
20mm
8mm
Finish
Brushed and polished
Water Resistance
100m
30m
Caseback
Solid
Transparent case back with sapphire crystal

Crystal & Dial

5 specs
Crystal Shape
Flat
AR Coating
Yes
Both sides
Dial Color
Black
Blue
Indices
Applied
Diamond indexes
Lume
None
Super-LumiNova

Movement

6 specs
Caliber
9S65
L899.5
Beat Rate
28,800 vph
25,200 vph
Jewels
25
0
Hacking
Yes
No
Hand-winding
Yes
No
Complications
None
Hours, minutes, seconds and date, Moon phase display at 6 o'clock

Pricing

1 specs
MSRP
$5,200
$2,950

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What people say

Owners + reviewers, side by side

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

Grand Seiko SBGR321

Grand Seiko SBGR321 owners and reviewers widely praise its attractive design, compelling dimensions, and robust movement. The watch features sharp case lines with contrasting brushing and polishing, a 40mm steel case that provides presence without bulk, and 100m water resistance. Its sunburst blue dial, inspired by the dawn sky over Mount Iwate, showcases Grand Seiko's signature finishing on applied markers and hands, with a red-tipped seconds hand. The 9S65 automatic movement is noted for its precision, running within specifications, with one source reporting a +5 to -3 seconds a day rate and a 3-day power reserve. A blue rotor with a crimson rim, also inspired by Mount Iwate, is visible through the display caseback. On balance, owners and reviewers rate the Grand Seiko SBGR321 highly for its exceptional finishing and compelling blue dial design at its price point.

Longines PrimaLuna

Owners widely praise the Longines PrimaLuna for its stylish, understated design and comfortable 26.5mm and 34mm case sizes, with some preferring the quartz for its lower maintenance and others the automatic for its craftsmanship. The automatic movement, an L899.5 or Caliber L899, offers a 72-hour power reserve and exhibits consistent accuracy averaging a loss of 1.3 seconds per day in testing, though it runs 3-4 seconds slower on the wrist. The redesigned collection features a curvier case with contemporary lug integration and is available in steel or bi-metal. On balance, owners and reviewers appreciate the Longines PrimaLuna for its elegant styling and reliable automatic movement, though some find its brand prestige and design less compelling compared to certain luxury alternatives.

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