Discussions

I am in the planning/research stages of renovating a bathroom.  
 
With all the hype/rebate information in the media lately regarding low-flush toilets, I am confused to say the least.  
 
Although initially pleased with the positive aspects of low-flushers, I also have some concerns.  
 
1) How much money should be spent for a "good" low-flusher? $350.00 and up? To me not being in the flush business, a toilet is a toilet is a toilet.  
 
2) Do you water pipes (inside and outside) need to be on a certain slope/angle for these toilets to be as efficient as they are being touted for? With incorrect sloping/angling, will there be more clogs and calls to the plumbing, thus saving water but spending considerably more for service calls?  
 
3) If the piping is an issue, how can I determine if the piping inside and outside my house is compatible to get the most efficiency/savings from a low-flush?  
 
4) Do I just leave these decisions to the plumber and hope for the best?  
 
Any suggestions/experiences/advice appreciated. Thanks.