The focal length 55mm I have received a trial basis and Schaerfereihe (also focal length 55mm) compared with EF-S 18-55 IS II. The EF-S 55-250mm was sharper, especially in the corners!
-> That was an eye-opener. In this lens I stay definitely.
A lens hood is not included. The backordered from me Profox LH-63 does a good job. It fits perfectly and can also save space in transport mode attach to the lens.
The price of the lens are unstable. In addition there are options in winter and summer Canon CaschBack.
The current firmware of the EOS 600D (version 1.0.2) does not have the Lens Correction Data. Also Lightroom 5 Vers. 5.7 and Canon DPP verse. 3.12.51.2 also do not have the Lens Correction Data (as of 01/2015).
But it does not matter. In my view, the objective technically mature and needs barely an extra correction.
We have attached two photos with EOS 600D and EF-S 55-250 IS STM from the same POSITION:
left: f = 115mm
right: f = 250mm