Toyeast carries plastic linked tracks that will fit their VS and your Marui tanks.

Since I only have Heng Long tanks, I'll speak to them. Each model has its own issues. There are basic things that should be done with each new tank to make it more reliable. If you don't do them, you'll have a pile of broken parts like I do! Once done, the HL tanks are very robust and reliable and a lot of fun to drive. Bigger tanks handle outdoor terrain better IMO. Get what you like, do the required mods, follow the recommendations and you'll have an enjoyable experience.