I have been playing a lot of Bryant's mod and have had some very good, tough space battles. I was wondering if anyone knows if Interdicters will help with planetary defense tageting my starships, or if they only effect hyperspace and missles/torpedos? Looking for some way to counter or reduce damage from ion cannons and hypervelocity guns besides having lots of ISDs to soak up damage.

Having a hypervelocity gun on a planet is a great investment and if you have a strong land garrison, ATAT, base shields, turbo laser towers, etc you can't easily lose control of either the space of ground areas. The only pitfall is this is only possible on planet with lots of building slots.

After playing with the Interdicter last night, it seems that it is so specialized as to be almost useless. No weapons at all, just the gravity well/anti-missle fields. Perhaps it may be usefull for trapping a rebel force and destroying it, but considering the unit cap, and its lack of weapons, you may prefer another VSD in your fleet. Saw little or no effect on missles and the enemy was not at all interested in detroying it. Maybe I'm missing something, or maybe the demo version of the ship is not complete. Anyone else have thoughts on this?

Don't put to much faith into how ships handle according the mods. Although they are great mods and give a real insight into how this game will play, they are still using ships that technically weren't supposed to be used and as such the stats of the ships and even some special abilities will be flawed. Plus the demo comes from an earlier build and most of the ships stats will ultimately change come the full release.