Woody's summarised it well.
I have two of each VFC and TM, I would say if I could only have 1 it would be the TM, it has never skipped a beat the VFCs feel better and perform nearly the same with the hop upgrades, but the TMs just work OTB, never had an issue with any aspect of it inc mags, can't say the same for VFCs.
Both are great though, once you get 1 gbbr it's very hard to stop, they are so much fun, TMs the best staring point imo as it just works, the M4A1 won't feel like a toy compared to an AEG, it feels great full stop.