All that follows us purely my opinion. I know there are some that disagree with me.
I couldn't say. I like bondage tape and I also like ropes. I've never used handcuffs or the leather restraints.
Proper rope tying is an art in my opinion and it takes a while even when you know what you're doing. Starting with one single piece of rope and binding her entire body is pretty fucking awesome IMHO
Think of it like this. You live in New York and you need to go to LA. Handcuffs and leather restraints are hopping onto a direct flight out of JFK to LA. Bondage tape is a couple of connections and different flights, but rope play is throwing the wife in the car and driving cross country. You don't drive cross country when you could fly unless you value the experience of driving. You don't spend an hour (or more) doing a full body bind that could be achieved in 5 minutes using spreader bars and bondage tape unless your getting something out of the act of rope work. There's no masters level tool kit you're working towards. Use the tools that you can use safely and give you what the both of you are looking for.
If you get off on using the bondage tape and want to take the next step I'd recommend 1.5 inch satin ribbon. Go buy 100 yards of it and start tying knots. If you get into anything complex plan on cutting it off. You won't get all the knots out. If you're still on board after that go invest in high quality rope.
My recommendation was based on bondage tape being dirt cheap, disposable, and easily removable with a set of shears. I thought it offered the maximum experience for the minimum risk.
I'd actually recommend that universally. I didn't buy a spreader bar because I saw it and wanted to figure out how to work it into play. I wanted her to quit bending her knees and squeezing her thighs together so I found the tool that achieved what I wanted.
TL ; DR Don't chase the tools. Chase the experience and find the tools that get you where you want to go.