Topdon ArtiDiag600S vs Artidiag800 BT vs UltraDiag

What is the difference among Topdon ArtiDiag600S AD600S, Artidiag800 BT AD800BT and UltraDiag diagnostic scanner?
Check the table comparison below:

Item	ArtiDiag600S	ArtiDiag800 BT	UltraDiag
Display	5 inch TFT
RAM	2G
ROM	16G
Battery	1500mAh
OBDII Code Reader	√	√	√
Full System	X (PCM TCM ABS SRS)	√	√
Read DTCs	√	√	√
Clear DTCs	√	√	√
Data stream	√	√	√
Read ECU information	√	√	√
Bidirectional Control	√	√	√
Key Programming	X	X	√
Service Functions	8	28	30
Vehicle Coverage	110+	110+	70+
AutoVIN	√	√	√
Software Update	Free	Free	2 Years Free Update
Language	17 Languages: English, French, German, Spanish, Portuguese, Russian, Japanese, Italian, Polish, Turkish, Dutch, Hungarian, Slovak, Korean, Finnish, Czech, Arabi	17 Languages: English, French, German, Spanish, Portuguese, Russian, Japanese, Italian, Polish, Turkish, Dutch, Hungarian, Slovak, Korean, Finnish, Czech, Arabi	11 Languages: English, French, German, Spanish, Portuguese, Russian, Japanese, Italian, Korean, Simplified Chinese, Traditional Chinese