Looks good on my HTC One, except it is kinda hard to click on menu buttons. On that phone size the menus are usually get collected under the menu button and drop-down on click in large font.
As a new visitor I was puzzled by the screenshots on the home page – they change way too fast, I do not have time to actually absorb what they show.
Those images look OK on desktop, but on phone they are a) too small to really see anything and b) they are not under my control, so they are annoying. I believe the common solution now is a slider controller where I can choose the shown image either with clicks on smallish dots under the slider, or even with swipe movements.
Also, some of those screenshots apparently show the value, but what value is not clear to me: for instance, a screenshot with Mr and Ms Adams names has a curious upside-down text; I guess those are invitations? I believe a short wording in large font over that screenshot a-la “Print Well-Designed Invitations” would help to understand that benefit.
P.S. The price seems too small foo all tiers.