We are using rotor gene 5 Plex with HRM... we have not faced any problems since the past 2 years. Its performance is good and a very sturdy equipment. 

All these machines will allow you to obtain good PCR results. (The conveniences of these machines - a matter of habit). However, the format of the Rotor Gene is less convenient - rotor does not allow the use of PCR-strips or plates, which are convenient for mass PCR screening + some Rotor Genes have a troubles with some channels (FAM especially - may fall after 3-5 years of using). I would use Quantstudio 5 - a more modern processive device without rotor.

If you are considering purchasing a qPCR, I urge you to consider ddPCR (droplet digital). BioRad makes a system - it's expensive, BUT digital (binary) PCR, with the software they provide, allows you to do Absolute Quantitation without the need for standard curves. So depending on what you're going to use the qPCR for, you may have a better method. You will need money for this (2-4x the cost of qPCR) but may save you a lot of time and bother.  Regarding qPCR, I've used CFX96 (and Stratagene MX3000-series systems) and have found both good...as long as you're running lots of controls and have good reproducibility.

If you are not worried about budget (3 quotation system) use QuantStudio-12K Flex Real-Time PCR System of Applied Bio-system. Very handy and hassle free diamond baby. My experience with this machine resulted many breakthrough in wound healing research.