This store is a great addition to the fountain pen landscape of Toronto. The owners are super-friendly and will help you with any questions you might have. The store carries a good variety of inks. Of particular note are the remarkable German inks by Rohrer & Klingner. They also carry a good selection of very high-quality journals, notebooks, and notepads. Fountain pen enthusiasts will be happy to find silicon grease, syringes, and the like. The variety of fountain pens the store carries is good, but not exceptional. The prices are fair.
The one pitfall of this store is its size. The place is tiny and the owners are clearly struggling to display their items. I think they could do some reorganization and drastically improve their display. In particular, the way pens, inks, and ink samples are displayed could be improved.
All in all, I give a big thumbs up to Wonderpens. If you live in Toronto and enjoy the art of writing, this store merits a visit.