I have had very good results with Gargraves flex. A few reflections:
Get new track. Old stock does not bend so well and is more likely to kink. (The ties dry out, and won't slide down the rails properly.) Of course, you can always use old stock for straight sections, or places with poorly-laid track, where kinks might be expected.
A cut-off disc in a rotary tool is far and away the best method for cutting this stuff. Not optional in my opinion. Like others, I also highly recommend the 90-degree attachment. You can do without it, but it is so much nicer to be able to make the cut exactly where you want it the first time. (Without the attachment, your first cut will always be sloped, as the track you are cutting off gets in the way of the body of the tool and prevents you from holding the disc perpendicular to the table. Once you get the excess track out of the way, you have to make a second cut - which will still not be quite vertical. Annoying.)
Dewey Trogdon posted a nice description of how he bends Gargraves here: https://ogrforum.ogaugerr.com/...198#5512461199712198 I would only add that, on tight radius curves, you need to drive the outer rails back home a little at a time as you go.
One of the great advantages of flex track is that you can include easements! Easements are easy to plan (at least on paper; no idea about software), and easy to plot on the layout. You just leave a gap (which differs depending on the radius of the curve) where the curved track meets the tangent. John Armstrong wrote up a detailed description in his book Track Planning for Realistic Operation, but here is a quick and dirty summary: https://mrr.trains.com/how-to/...or-model-train-track
Making joints on curves is something of an art, which I have yet to master (though I would call my efforts acceptable). One thing you could do to avoid this is to use Gargraves for the easement, and then run it into a piece of sectional track. I did this at one spot on my layout: This curve is actually O-36.
I hope you take the flextrack plunge. I could never have had the layout I wanted if I had to rely only on sectional track. Even with all the sizes they make now, sometimes you just need an oddball curve for the space you have. And everything looks so much better on eased curves that there's really no reason not to use them, and the only way to get a real easement (other than handlaying) is with flex.
