Would like to share my experience on the following brands:
1) Mitsubishi Electric - Reliable brand as it has been in the market for many years, other than the ad by Jack Neo, it has been quoted 1 of the cheapest spare parts among other brands. It has a good back up servcice for its products.

2) Mitsubishi Heavy Industries - Has also been in the market for a while but major in big AHU and industrial air conditioning. However, does not have strong back up service group. Tried its invertor muilti split system a few years back, but was disappointed when it started to break down in 3 years time (Not sure abt the current ones). Nonetheless, the price are cheap for a system 3/4 invertor system

3) Panasonic - Previously known as "National", has been very famous in both Singapore & Malaysia in the early to mid 90s for its reliable compressor and spare parts does not give problem even after 5 - 6 years. After taking over by panasonic, it still retains its reliablilty in the market. Also famous for its built in air purification with the air con system.

4) Daikin - Daikin has been established in Sg for more than 30years. A reliable brand to trust not just in sg and also other countries. Has very strong backup service team. The are so call the first brand to introduce the invertor system. However, Daikin are well known for its expensive system and the spare parts can be very expensive when you need parts replacment.

5) Toshiba - Rumour said that that they inverted the invertor system but due to funding probem, they sold the invention to daikin. But they are the first to introduce the CFC free R410(if i remember) invertor system. Was very popular in the year 2000 to 2005. Still holding strong until today, but has not that strong back up service team and spare parts can be ex too. Although they have merged with Carrier, they are still ppopular in the market.

Above are just my opinion on the brands i come across with during the pass 10 over years in this trade.