Cheap CX5M
I think a CX5M is a very nice MSX so I would buy it if it were me 
. Good looks and solid build.
Whether it’s an SFG-01 or 05 doesn’t really matter unless you plan to use Yamaha’s software with MIDI. The MBIOS 2.0 ROM is the biggest difference. Also, it’s fairly easy to upgrade to SFG-05.
Side module to cartridge slot adapters were made by Alexey and Repair-Bas.
I have the opportunity to buy a Yamaha CX5M at a very low price. But is it worth it ?
If the price is very low, I would go for it! This machine is on my wishlist, only the price is holding me back... 
Good choice! The SFG will certainly work fine, most likely the CX5M is also fine. These machines are built extremely well (for use by musicians 
)
Now that it is in my hands, I can reveal the scandalous price I bought it for ......... 30 euros ! 
Still in its original box, complete with dividers and polystyrene blocks, all in very good condition. I even have the small printed cardboard color overlay that was used to remind of the main keys used while playing the keyboard. The only thing missing is the manual, but that's OK.
I haven't had the time yet to test it, but I'm quite confident, as it is overall in very good state. The gentlemen I bought it from is the original owner, who bought it in the '80s to play some music.
That's a steal
Man, the question of "sould i buy it" becomes really hilarious with ths price label, really. I boughе one with broken LVA video encoder chip which i had to replace for 50 EUR