This review was originally posted on VersionTracker.com. I have been using Zinio since it first came out and have only had the download problems once or twice early on. I used it with Panther and with Tiger (10.4.1) - just downloaded the August issue of Macworld in fact. Try tweaking your Network prefs - I've found that by switching the Web Proxy on and off - many download problems have been solved. Also I have not tried Zinio with any other mags so my experience is limited to one mag.
I love reading Macworld with Zinio - it's fun to use and has great features like hyperlinks in the articles etc. I also like having it check for new issues and downloading them in the background. When it's ready I get a dialogue asking if I want to read the latest issue. And I enjoy using the keyboard shortcuts for navigation. I can kick back in my chair not tethered to the mouse and relax while reading the mag. I couldn't be happier with it.