Pittsburgh has a rather eclectic mix of housing styles, including its rowhomes.
Wood-frame vinyl-sided (and rather ugly) rowhomes are common in the traditionally working-class neighborhoods (Troy Hill, Polish Hill, Bloomfield). The architecture is unrelentingly plain, but generations of incremental modifications have created interesting and distinctive streetscapes. Here is an example from Troy Hill:
A collection of North Side neighborhoods offer the finest rowhousing in the city... mid/late 1800s Victorians catering to the upper/middle class. These are from Allegheny West's Beech St.:
The Mexican War Streets (also in the North Side) is interesting due to its complete lack of uniformity... as with most of the city... it was developed lot-by-lot as opposed to block-by-block. The architectural contrasts are striking and create a visually engaging streetscape.
These simple brick mid/late 1800s rowhomes are typical of large historically working-class neighborhoods like Lawrenceville and South Side. This photo also gives an example of the sloping row, common in Pittsburgh due to the turbulent topography: