I highly recommend that you try out both versions before buying. Most people that I've talked to that have bought manual treadmills never used them because they were too difficult or awkward. I had one briefly and returned it the next day, lol. I love my electric treadmill. Every now and then, though, someone will pop up that loves their manual treadmill, so maybe you'll be one of them
Have you considered something like Leslie Sansone's Walk Away the Pounds? A LOT of our members have used it for a long time and love it.