Which is better for standing all day?

The 990v3's softer, thicker midsole cushions more underfoot, which most people prefer for long standing shifts. The 990v4 is firmer and more stable, so pick it if you want support over plushness.

Both use a rubber outsole and suede-and-mesh uppers with Made in USA construction, and owners report similar multi-year life. The v4's firmer midsole resists compression slightly better over time.

Is the 990v4 worth stepping up to over the v3?

Only if you want a firmer, lighter, more stable shoe. If cushioning and the chunky retro look matter more, the v3 is the better fit.

Do they fit the same?

They run similarly, both in a broad size run with wide options. The v3's bulkier toe box feels roomier, while the v4 fits trimmer through the midfoot.

Which is better for wide feet?

Both offer wide widths. The v3's roomier toe box suits very wide feet better, while the v4's wide width gives a more locked-in fit.

New Balance 990v4 vs New Balance 990v3

Both are Made in USA 990s with the same gray suede-and-mesh formula, so the choice comes down to midsole feel and fit. The 990v4 has a firmer, more stable ride and a slightly sleeker upper; the 990v3 has a softer, plusher ENCAP setup and a chunkier look that many owners prefer for all-day standing. Reviewers and long-time 990 buyers treat both as near-indestructible daily shoes, with the v3 getting the edge on cushioning and the v4 on support and a cleaner silhouette.

Choose the New Balance 990v4 if you want a firmer, more supportive ride and a slightly trimmer upper for everyday wear.
Choose the New Balance 990v3 if you want the softer, plusher midsole and the chunkier retro look that 990 fans keep coming back to.

Prices

New Balance 990v4: $89.95 at eBay (checked today)
New Balance 990v3: $69.90 at Walmart (checked today)
Difference: the New Balance 990v3 is $20.05 cheaper than the New Balance 990v4 today