Most consistent force feed loader?
You don't want a halo B or an invert too, they are basically the same, too heavy, can crush paint...way inferior to rotors and prophecies.
Since you are looking to be on a budget, the BEST bang for your buck will be a perfect condition prophecy. You can get one used in really great shape for 60-70 dollars. They blow away old halos. Way lighter, they hold a good 50 more balls..way more consistent, virtually jam free. Way more durable.
My favorite really cheap loader is the Evolution 3..only on guns that are long out the back though, like a tippmann or an autococker. They are really consistent, light weight, and never crush paint. Awesome hoppers. Of course their flaw is their typically weak shell..but just tape it as it cracks and don't worry about it and you will get your 30 bucks out of it :P