Wish I'd got a Combat Machine as my first gun, instead bought a sh*tty CYMA M4...which has next to no customisation (e.g. other RIS and handguards won't fit, no threaded barrel, my Magpul PTS stock wobbles on the buffer tube) the RIS wobbles etc. On top of that they have shite internals too. It cost about the same price as well, so I'm annoyed.
I could afford to get one but I've already spent a lot and we have too many (according to my dad, so no more now for a year -except for a pistol- until I can get my own defence)
As the others said, you won't regret it. Very nice guns for the money.