Sometimes two isn't better than one. Exhibit A is the Sony Tablet P, which sported dual 5.5-inch displays that you could use either laid flat or clamshell style. While small enough for jacket pocket, the P was way too big for your jeans and it cost a fairly steep $549 (or $399 with a two-year contract). And even though some of the apps stretched across both screen, you couldn't run two separate apps simultaneously like today's Galaxy S4. Worst of all, the P was instantly dated because it didn't support AT&T's LTE network. It was HSPA only. Why bother?
More: Top iPad Alternatives