I enlisted Homestars to help me find a reasonable A/C vendor. Within minutes, Convertible had replied to me. Their prices were reasonable and Chris was attentive and patient. At no time did I feel pressured to choose a more expensive (higher SEER) model. In the end, I chose a 16 SEER Lennox.
One word of advice... read the fine print. They make it seem like the warranty is 10 years parts and labour without any additional fees. However, upon closer inspection of the fine print, the labour warranty is only valid with participation in their protection plan. Despite this, I would choose them again. However, it did give me some pause.