Upon buying Poshe, I was disappointed to find out that it costs about $7-8, which is only a couple of dollars below Seche. This meant that if the top coat was measurably inferior to Seche, it wouldn't be worth it to buy Poshe instead of Seche. So home I took my little bottle, happy for an excuse to change my nail polish immediately. Poshe applies quite smoothly and nicely, leaving no bubbles, and keeps the polish chip-free for a reasonable amount of time. However, it did not measure up to Seche's glass-like shine and length of wear. Seche will keep your polish on at least 4 days no problem, while Poshe is pushing it at 3.
Also, I was severely disappointed once I reached the bottom half of my bottle. It has all the same problems as Seche (heavy bubbling, extreme thickening, etc.), with even worse thickening! I felt like I was trying to put glue on my nails. :( I've gotten much better results from several of the drugstore top coats I've tried so far.
The verdict: Poshe is nice, but not worth it. Buy Sally Hansen Mega-Shine, and get the same results a whole lot cheaper, or cough up the $10 for Seche Vite.