For me, what counts most when buying themes, is the support level. Even the best theme, should not fits 100% your personal requirement. So Materialecho, Swift, Xmagazine, the 3 themes that I bought from DohTheme, were not an exception. I needed some design changes, you know all those boring "Moving that part to top", "Remove that block", "Change that color". The Support level that I got was on superior level. I was getting replies in a couple of hours. Mostly less than 3 hours. And not only simple instructions that in most cases need to ask again to clarify things, but I've the fixes done by them, directly to my website. Have been surprised. From that (important) point and then, all 3 themes have a nice interface and lots of settings to fit it to your special requirements. Finally I choose Xmagazine, not because it was the best (in my opinion all 3 themes have a nice design), but it was closer to my needs. Meterialecho is great, in a very low price, but I don't like so much Google Material design.
