Proto 1000 is not a higher end, thats actually the low end. However they're still better then plain Life-like. Its the same with Bachmann, Bachmann Plus & Bachmann Spectrum.
As Paul aid BLI/PCM, Kato, & Atlas (gold & silver, or even plain Atlas, excluding trainman) are the higher end stuff, along the likes of Genesis. Altas Trainman would be like buying Athearn RTR, or Blue Box (though trainman is RTR if I'm not mistaken). Blue box is a fan term, for Athearn kits.
The new Walther's Gold line would be a higher end line too.
Most Walther's, you cannot go wrong with, such is the case with Athearn, Roundhouse, McKean, Stewart/Bowser, Atlas, Kato...