I have the few main types of lawn edgers - a 'stick' edger that attaches to the whipper snipper, steel blades instead of trimmer line, small 2 stroke walk behind edgers,
6 wheel alrohs, and 3 wheel Tilt a cuts (and Pionex - don't know if you have them over east but just a 3 wheel edger).
Never used rotary scissors but have good reviews from friends who have used them on manicured lawns only.
Whipper snipper attached ones are a pain, not great on you back and I struggle with them, ditto with blade instead of trimmer line on standard trimmer.
I love my little 22cc Weedeater GE21 - a little 2 stroke walkbehind edger - 50 times as maneuverable as anything else. You can still get similar from Ozito and a few others.
If you have 500m of straight or large radius curved edges that are feral, then a 3 wheel edger is the best.
There are a few on the market, The more expensive over here being Mowmaster and MEY - great traditional edgers.
Masport do two that are identical bar the engine - the cheaper one uses a 80cc Chonda (yes - 80cc), or 127cc Briggs.
Go pretty well, only downside is the OPC control so you have to hold the handle all the time (however you have an off switch on the engine if the OPC bar was somehow, er, rendered inoperable.
Parklander do a modern take on the victa TAC, with either a 87cc chonda or 196cc. Good thing about these ones is that your height adjust is up on the handle, and only tensions the belt when you select a cut height - so you can line up with a stationary blade and then go.
The last option is Atom edgers, again very good. They now only make 2 stroke ones with 'Atom' engines - which are ryobi (though it must be said a very good ryobi engine that was discontinued - I have 4 of them and they are marvelous. 4 strokes are Honda.
Up til last year they made them with Zenoah engines - only hope would be store stock now though