The 4R series of Seiko Movements are the most entry-level of all Seiko mechanical watches. Seiko reserves their mid-end 6R for pricier watches, and their highest end 9R for Grand Seiko.
Certina is actually a brand under the Swatch group and as such, benefits from ETA (the world's biggest movement maker) now supplying to all Swatch group brands (including the famed Omega, Longines etc.) almost exclusively. However, they are one of those that no one really recognises.
The Powermatic movement was actually first released for Tissot (also a Swatch group brand), although deemed entry level, is a fairly new movement with very long power reserve (80 hours). This means you can go for 3+ days without worrying about winding. Given that it's also automatic, you can even afford to take a 3 day weekend and be assured it will be find without winding when you pick it up the next week.
So here's the toss-up:
Brand Equity (Recognizability) + Heritage: Seiko
Movement Quality / Convenience: Certina
Aesthetics: Up to you.
Hope this helps somewhat.