Q1. Whats the difference between scooba 380,385 and 390?
A1. 385 = Europe model (S'pore agent selling this due to voltage similarity)
380 & 390 = USA model (voltage of charger is USA 120V, requires Voltage Convertor or charger modification)
380: Version 7 software (found on S/N) if made after Sep 2011, Version 7 gives 30% longer battery runtime by virtue of power tweak
Version 7 Scooba 380 also have the orange colour code for all the things to rinse after use, the Water Tank handle got slightly different design (dunno if it helps prevent handle breakage, a common thing)
390: Version 7 software, orange colour code, whole robot change colour to Dark Grey, iRobot excluded 3 accessories found in Scooba 380: 2nd virtual wall, External Battery cradle & Waterproof resting mat
385: probably version 6 software, just like Scooba 390, doesn't come with 3 accessories found in Scooba 380: 2nd virtual wall, External Battery cradle & Waterproof resting mat
Although I'm still using my faithful old version 6 Scooba 380, my customers who're using Version 7 Scooba 380 reported that Scooba clocked ~130 mins total runtime, very inline with iRobot's claim of 30% increase.
I need to clarify though, to accurately compare, we need a standard environment (ie. floor friction, amount of furniture, amount of water filled).
Meaning, if u test in ur home, results may differ slightly vs testing in my home. Cos a slippery floor makes Scooba do the "Turbo Boost" to free itself, lotsa furniture means constant changing of direction & loss of momentum, water filled is essentially weight that Scooba needs to carry.
Since day 1, I fill less water for small room, cos for Scooba to piggyback extra water which won't be used until next room, is a waste of stored battery power.
Q2. My place is homogeneous tiles in the living room and parquet in the bedrooms... total area around 1200ft.
A2. Roomba & Scooba will work fine on homogeneous tiles & parquet (assuming has Polyurethane coating).
1200 sq ft is big, but in reality, that includes many areas that u won't let the robots go anyway.
Q3. Lazy to check out the features...
A3. Welcome to Lazy Club, come'on... stop kidding urself, all robot users are lazy.
Q4. but i want something that i can program to clean at a specific time...
A4. Only Roomba can be programmed for auto-start
Q5. and if i get the combo, do i let both run at the same time or which one do i start first and in what interval?
A5. Just don't let Roomba & Scooba cross territory, Roomba tires will leave tire tracks on moist floor & u won't want the brushes to sweep water cos it's messy.
Always Roomba first (ie. sweep), then Scooba (mop). Logically, u won't mop first then sweep right?
Thanks for the detailed explaination. So i have to get scooba 385 rather than 380 or 390 in order not to mess around with the voltage or adapter or converter?
. Ease of use and maintenance is important to us, as we don't have much time on weekday nights and there are other chores.
its not quite that bad, if the floor mopping or washing can go auto, it's quite a relief.
Almost like a museum of household tools liao. Neat-freak + cache of machinese + manual labout, Josie will be very busy. I see in the pictures that Josie can look stressed too 
