One of the more remarkable traits of successful golf course superintendents is their ability to adapt and efficiently solve unique challenges at their site. A compelling factor in any supt's. operation is the need to efficiently utilize the labor hours available. I think this reality has been, and will continue to be, a significant influence at most facilities.
As a result, chemical edging has proven to be a viable alternative to physical edging at many warm and cool season grass facilities. Plant growth regulators have become widely used, not only to reduce mowing frequencies, but also to enhance turf quality on tees, greens, and fairways. Furthermore, non-selective herbicides are sometimes used to reduce warm season turf encroachment.
When physical edging does become necessary, I would suspect that string trimmers and/or reciprocating edgers are the favored choices. Use of these items allows the supt. to neatly trim the overhanging grass without gouging into the edge. There may be a need, on an annual or semi-annual basis, to use a power/sidewalk edger (or manual labor) to restore a desired smooth edge. Certainly, there is some potential for loss of shape over a period of time as this work is performed.
There has been a bit of a trend toward alternative grasses on bunker faces and surrounds to help cope with some of the maintenance challenges. Zoysia is becoming more widely used in warm climates due to its significantly slower growth habit, improved drought tolerance, and winter hardiness compared to many bermuda varieties. Dunlop White provided an interesting description of the zoysia bunker surrounds at OTC by referring to them as having "an upholstered look". I have also seen buffalograss used in several situations although it has failed quite miserably in the desert southwest.
Improved fine fescues are finding their way onto several bunker faces that were formerly Kentucky bluegrass due to their comparatively improved drought tolerance and reduced fertility needs. Fescues also provide a significant contrast to KBG in terms of color and texture. And, as most here already know, fescues can provide a pleasing effect and contrast when left unmowed.
Sand deposition is a significant problem on bunker edges. Brooming, compressed air, and high pressure water application are some of the means by which supt's. can remediate this problem. However, it is but one source of potential bunker challenges. Others include: erosion, damage from foot traffic, entrance and egress damage from mechanical bunker rakes, improper raking practices, sand contamination, inadequate or damaged drain lines, poor construction, improperly installed or ineffective lining materials, a sand that does not meet favorable performance criteria, a membership that can't decide between firm and soft playing conditions, etc.
While I'm sure that I've only scratched the surface of the answer to your question, I hope this helps.