If there is no defined edge it is hard to make a decent edge with just a string trimmer,but once you have made a nice edge from a edger it is very easy to "freshen" it up with a string trimmer and still looks good .
i would recommend the echo split shaft trimmer. i bought that and you can switch attachments. i have the trimmer and the edger attachment. i can switch them in about a minute. well worth it and not too much more. i also bought the rotary broom for it. they all work good.
An edger or an edger attachment is definitly worth having. A nice clean edge on sidewalks,driveways,etc. is just another way of advertising that you do good work.Word of mouth advertising by customers and their neighbors is just another way of getting more lawns near where you are already mowing.
Go on and get a dedicated edger. If you ever plan on having help, both of you can edge/trim at the same time. If you plan to stay a one man operation the split shaft might be a good idea. I've never used the split shaft design, but I do own Echo edgers, trimmers, and blowers and think they are all great.
The stick edger attachments or dedicated stick ones work for light edging like maintaining a previous edge, but it is simply not enough power to do neglected edges or those that have never been done before.
If you can afford it, get a wheeled edger, use it in the Spring and maintain with a trimmer all year. You can use the wheeled ones also for beds, installing edging, etc. If you ever had a lot of edging like a apartment complex you would dream of a wheeled edger after a few hundred feet with a stick edger.
Thanks for the info,I called the echo dealer yesterday and he saide not to go with the model that switches heads its more for the homeowner.The one he reccommended was the heavy duty one with a lot of power for 400.00
Bryan, which model was he referring to. I paid $329 for mine and it has all the power I need. In my previous post I didn't mention how often I used mine. On fescue I only use it once a month and a trimmer the other 3 weeks. and for bermuda I alternate between the edger and trimmer. Although the edger will edge faster it does take time to switch machines. The edger gives a much crisper look but isn't required with each mowing. Good luck with your decision.