I looked into this ages ago and it seems many people were having mixed success with the "T" range ovens. I ended up building my own. To speed things up I used off the shelf components and the results are fantastic. I wrote a little article here:

http://www.firewing.info/pmwiki.php?...low-Controller

I've profiled the oven and there are very little deviations in temperature across the horizontal. This means I can easily reflow a board up to 9" x 10" (22cm x 25cm) without any hot or cold spots - all the paste reflows. Importantly, the results are reproducible and consistent. One thing I would strongly recommend is that you can monitor the profile temperature in real time. This ensures you can see how close your oven temperature matches the paste and / or component profile. The cheaper ovens allow you to set a temperature profile, but how do you know if your oven is actually doing that? Finally, I would also recommend an oven with a fan (convector) to stir up all that hot air...