I'm using a Solo2 and the same Customized List that I used on the same decoder but plugin v2.8.3. The only difference is that wheras on v2.8.3 it used to take less than 5 minutes for the same Customized List, with v3.0.6 it took me 13 minutes. For the Non Customized List there is no significant difference, maybe with v3.0.6 it is faster as it takes less than a couple of minutes. It is only a slight problem for me that I can live with it as it compensate for the frustration of cleaning the Channel List every time I update it.
That's actually huge difference.
I've no idea on how the plugin works, but It may depends on other factors in addition of decoder type.
Maybe you're comparing one run on flash and the other on a different BH Universe. In this case the time may also depend on how fast is your USB stick.
Please, try to test in same conditions.
You may also compare with SVDownloader which does the same filtering stuff, and it works in RAM, so you may see different performance.
This is just a try to isolate the issue.
Raist