I bought a Suzuki DF140 in August of 2005. So far it has been great.

The Harbor Patrol nearby is running 2003 DF140s on their boats. The
dealer I bought my motor from had one of the boats in the shop when I
was looking around. The hour meter was at 760 hours. The motor has been
run hard in salt water and seemd to be holding up just fine. There was
an older boat in the shop getting a new DF140 installed to replace an
old 200hp motor. I estimate that the boat was about 23' with a fair
size cabin. The owner was there and I had a nice chat with him. He was
repowering and going smaller. He could never use all of the 200hp
unless the water was like glass. It would pound the hell out of him. I
ran into him last week and asked how he was doing with the new moter.
He was VERY happy with the performance and fuel ecomony. He said he
added about 33% more range with the new motor and could run just as
fast.

The worst things you can do to a motor are sporadic use and poor
maintenance.

The biggest issue is what kind of dealer support you have. Go with the
brand that has the best dealer support in your area. The local Suzuki
dealer also handles Yamahas. If Yamaha made a 140hp four stroke I would
have considered it.

Many people like the new fuel injected two strokes. In theory, they
should be fine. In practice, I don't think that trying to run ANY two
stroke on an extremely lean mixture is going to have long term positive
results. It doesn't matter how tricky the systems are. When a two
stroke doesn't get the right mix they'll fail.