Hi Elsie:
if you are actually hill-walking or hiking, the rugged terrain demands a shoe with ankle support, arch support and sole support. For this, I always wear a Merrell, high boot with Gore Tex lining for waterproofing. This is for all day hiking with backpack.
For my long power walks around town, average 11-12 miles several times per week and walking on pavement, I use my regular running shoe. I am an Asics girl. I keep the Asics for running only when they are new, because they tend not to be as flexible as I need for fast walking when brand new, but the cushioning is ideal for running, of course. I am a heel striker, so I need thick heel cushioning for running. However, for walking, I need a fast push off from the fore foot and greater flexibility for toe-off.
So, here is what I do (a method that may be up for revision). I use the Asics gel GT 2000 series. When brand new, they are running shoes. After a year, or 6 months, depending on how much running I have actually done in them, they are perfect for power walking/long distance walking. The last pair of power walking sneaks I just retired as 'gardening shoes only,' I had used them as walkers for about 4-5 years, which is actually a tad too long. I was getting pains and aches because there is absolutely NO cushioning left in them, just zero. However, economics demands I use my gear as long as I possibly can!
I got a new pair, but unfortunately, Asics changed the fit slightly, and the new size 8.5 no longer felt so good, felt like an 8, so I had to go get a new pair. Power walking makes the feet swell, just as long distance running does. We long distance walkers suffer the same black toe and toe nail losses as runners if shoes are ill-fitting. So, now I have 1 pair of gardening shoes, and another pair I use for 'errands and about town shenanigans.'
I got a new pair and went up a half size to the Asics gel GT 2000 second series size 9: perfect! I got them from amazon.com because they are the model before this year's, and I got an excellent price for them. I had no choice but to use them as power walking shoes right out of the box. And, I am happy to say, they perform beautifully and have needed no breaking in! Last time I did my 11 miler, I shaved 6 mins of usual time. So........
I recently bought a brand new pair of Gel Kayanos (20% discount at rei.com). It is a superb running shoe. However! You need to know that it is a stability shoe made by Asics, for the moderate to heavy over-pronator/who weighs over 150 pounds-ish. It has fab cushioning, really like landing on soft pillows, and is excellent as a RUNNING SHOE especially if you are a heel striker. Kelly Coffey-Meyer also uses hers as her 'go-to' studio fitness shoe. However, I personally think that it has too much cushioning to make it an effective long distance/power walking shoe. It will not be flexible enough. I am saving mine as a running shoe only. It has a higher heel drop than most other Asics shoes (height differential between the heel and the toe) and this matters as you get older and lose flexibility in calf muscles and the achilles tendon. Too much of a heel raise can shorten the achilles if you wear that shoe exclusively. So, you'd need to make sure you stretch that calf and achilles assiduously to prevent problems with tendonitis. (I am learning this the hard way).
Does any of this help? So much of shoe buying falls to trial and error I think.
I have looked many times at the shoes many companies market to 'walkers' and I will never buy them. I think they are targetting someone who walks with her friends around the mall for 3 miles before the stores open, chatting the entire time with head turned sideways. This is not me. I'm thinking, it's not you either?!! Get yourself a good running shoe that offers the perfect compromise between flexibility and cushioning. If you go to runnersworld.com they have multi-annual reviews of shoes with a really cool and helpful scale for each shoe that evaluates this all-important cushioning versus flexibility issue.
Clare