I bought my EF-S 18-55mm as a part of the canon xSi kit. In my mind's money-eye it seemed the lens would add value to the camera. I'd already had enough lenses to be a happy photo camper. After playing with the lens for a day and straining my eyesight over the fresh snaps I decided to buy a B+W UV filter because I thought the lens' front element was worth protecting. I'd suspected I might be using the lens more. Unfortunately, the lens' mechanics cannot be as easily protected.
I consider the lens' weight as an important discriminant since I go on hikes and like to trim down the gross weight in such adventures. On the other hand, there are people who take hand weights when they go on walks. I try to evaluate my needs but I am not always sure how certain features will turn out in the field when I finally use them or not. The lack of excessive weight is a plus when I have to haul it but my camera jiggles happily in my hands when I need it steady for exposures critically close to causing camera-shake blur.
These considerations are important to me since I am too lazy to carry a tripod on my hikes (and mountain-bike fair-trail runs) and tend to take pictures when light is photographically strongest: early morning and late afternoon.
Now I find a camera (with the battery grip)-lens combo weighing up to a 1kg/2.2lb a very light package to carry and heavy enough to provide stability, comfort and grip.
This brings me to the point of how I feel using this lens for landscape photography. I think this is where I have most problems using it.
I find that overall, subjects are much sharper when the lens focuses on distances less than infinity. The scenery captured on the assumed infinity mark (the lens does not have a distance scale) has less clarity than subjects photographed at closer distances.
For landscapes, I prefer setting my focus to infinity by either setting the focus ring manually or having the auto-focus do this for me at a longer end of the lens, and then turn the switch to MF. This can be reckless because a random zoom lens needn't to be parfocal. Occasionally, I like to relieve the shutter button from the focusing function and delegate it to the AE-lock button. Anyhow, I am unable to tell when the lens locks consistently to infinity and subsequently I've been using this lens for very casual landscape photography. I haven't done any casual landscape photography in a while.
In terms of picture quality, in contrast to middle-of-the-road settings, I find the lens to be struggling with sharpness, color and contrast at very short (macro) focus distances. Various lens' "color" defects can be corrected nicely in DPP when shooting RAW.
Wide apertures are wonderfully comparable to expectedly better smaller f-stops. At the longest end, wider apertures than f/8 are notably less favorable when looking at photos fully magnified. Closer to its widest end, open apertures when light is light and contrasty "color" artifacts are less likely to show, and aided by the IS is where this lens wins the evening.
I don't expect inexpensive products to be stellar performers at extremes of their design, as I don't perform as well when pushed to my limits.
The EF 50mm f/1.8 (that I don't own but do the f/1.4) would fill in where the zoom is arguably "lackluster-sih" and provide workable portrait bokeh. Now that is an inexpensive and light combo that wants me to put more weight in my photo bag!
Picture quality related concerns are quite subjective and I tend not to worry about them. It helps that I have other quite capable lenses (none are L) so that I never think I am held down by my optics. I hope you find some time and look at photos I have taken with my photo-tools of which some were taken with a film camera bought used for $1.49 + sales tax.
Thank you for reading,
ps. both photos taken where the lens is most vulnerable (55mm). the photos appear significantly compressed here.
1st photo: f/8
2nd photo f/9.5