wblynch, I don't think anyone is trying to score points here. As I understand the Ti is an abreviation for Titanium which, in itself, is perhaps not so important. What is important is that the question asked was the difference between the OM4 and the OM4Ti. The OM4 has battery drain problems which the T or Ti (depending on the country, it seems) has resolved. It is also the most recent addition to the OM system and much less likely to require expensive refurbishment.