Both layouts can provide long work runs, but corners and internal distance must be managed deliberately.
L-shaped strengths
An L-shaped kitchen can leave the centre open for dining or an island and usually supports flexible traffic. The open side can also allow traffic to pass too close to the work zone if entries are poorly placed.
U-shaped strengths
A U shape can surround the cook with storage and counter space. In a narrow room it can feel enclosed, and long distances between the ends can create unnecessary steps.
Handle corners intentionally
Blind-corner pullouts, drawers, corner sinks and lazy-Susan units each trade storage volume, access and cost differently. Do not let a cabinet catalogue choose the corner automatically.
Check island temptation
An L-shaped plan often appears to “need” an island in renderings. Verify clearances and door openings at full scale before adding one.