I've been using Privateer Press spray primer for the last couple years, as it provides excellent coverage without obscuring detail. At $10 a can, it's cheaper than GW or Army Painter Primer, so it worked for me. However, I've heard good things about Rustoluem's new Ultra Cover Primer. At around $4 a can, it was definitely worth trying out. I couldn't find the standard primer, so I picked up the paint+primer. I also grabbed their matte varnish to see how it compares to Dull-Cote.
I tried out the primer on a base textured with sand and slate, which is about the hardest surface to prime that I have discovered. All of the small cracks are difficult to cover. The Ultra Cover Primer did a better job than anything I've used previously. It did leave some crevices uncovered, but fewer than other primers that I've tried.
I knew that the primer had good coverage, so I decided to test it on some models to see how it affected detail. As you can see above, it was able to cover the model well without obscuring any of the fine detail.
Finally, I tried out the varnish. It does provide a nice matte finish, similar to Dull-Cote. However, it didn't apply with a smooth finish. As you can see above, it left a slightly rough texture on the flat areas. This wasn't necessarily bad as it didn't seem to obscure any detail, but it is different and could be objectionable. It's possible that this was due to not shaking the can enough or something similar, so I'll keep trying it out.
In the end, the Ultra Cover Primer is a great product and a significant savings over the miniature specific primers. It's definitely worth checking out. The varnish also works pretty well, but it falls short of the high example set by Dull-Cote.
Also, I hope you enjoyed the WIP shots of my upcoming models. I plan to have them on the blog soon.