The one you show looks pretty good! I've had many that looked worse than that on projects I've done.
A comment on your tools. A coping saw is always going to give you problems with your main cuts. I use a coping saw only for cutting the waste to minimize the amount of chisel work.
The problem I think you are having (rounded corners on the pins and tails) is due to the flexing of the coping saw blade. If you want to continue with hand cut dovetails, you will need to use a different saw. The coping saw blade flexes way to much and it is too difficult to get a straight, flat cut. I understand that you are cutting wide of your marks and then using a chisel to trim, but that is just doubling your work - as well as introducing another source of error in your cut.
It doesn't have to be an expensive dovetail saw. Until just recently, I only used an 8" gents saw (~$20) for dovetails large and small. You can of course spend as much as you want, but a gents saw is a good entry saw (if you aren't bothered by the handle style).
If you are getting a choppy, uneven base line I would guess you are putting the chisel right on the base line and hitting it with the mallet to chop waste away. When you do that, the chisel of course cuts down, but the bevel also pushes the back of the blade into the baseline creating an uneven line. The better way to cut waste is to use the chisel/mallet to remove waste to within about 1/16" of the baseline, then use paring cuts with only hand pressure to remove the last little bit.
EDIT: Others replied while I was typing. It's taking you a long time to make them because you are cutting wide of the line and then chiseling back to it. If you had a decent dovetail/gents saw, you could cut right to the line and wouldn't need to do any trimming with the chisel. You'd just make your main cuts, trim waste with the coping saw and then do a little paring with the chisel back to the baseline.
"Good Behavior is the last refuge of mediocrity" -- Henry S. Haskins
Last edited by trc65; 10-12-2013 at 07:57 PM.