The 146/RJ and the 757 both have their pros and pitfalls.
The 146 to be honest has not really been exposed to its true niche market. I used to fly the 146 in Europe and that ain't the environment that it excels in. I am now flying the 146 in North Africa now and an auditor asked me what load I could lift from a 2000m runway with 40C OAT. I think I surprised him when I said that we could take a 'full house' with no problems.
Electric start means that a knackered APU means all we need is a GPU and not an airstart unit which are rare in the desert.
Also the high engines mean we don't chew up lots of sand, unlike the 737 in our fleet!
The 146/RJ does not shine when it is doing mundane city to city flying in Europe!