How is the sequencer, it always frustrated me before, assume they haven't changed it. other than that I'm tempted because its fun to use.
It's mainly linear.
For linear style sequencing where you play in your parts with a keyboard, it is one of my favorite sequencers. It is very straightforward and quick to the point. Reasons sequencer is like learning to ride a bike where Ableton is more like learning to drive a manual transmission car. In the end Ableton is probably more powerful but Reason is sometimes more fun.
It has some nonlinear aspects as well. (Eg non trigger able Blocks, Redrum drum machine pattern sequencer which is trigger able and the limited monophonic matrix pattern sequencer).
It's audio side though is limited (mainly for mixing and editing). What is great though on the audio side is its comping (my favorite out of any DAW), and time stretching (also my favorite out of any DAW).
It's piano roll though is horrid. Although it is decent for simple edits of notes. It sucks IMO if you are writing music mainly with the piano roll. FL or Even Live is much better in that department.
Lack of VSTs will be a hindrance for some but at the same time it has plenty of cool things hard to get in the VST world (eg Buffre a highly tweak able version of Live's beat repeat with plenty of tricks, Polar one of my favorite chorus units out of any DAW, Antidote a unique take of a synth designed for unison effects and multi saws). It also have the classics (Malstrom graintable synthesis, and Thor jack of all trades but master of none).
It's power comes from combining stuff with combinators and CVs.
Live is more powerful with Live Racks and M4L but a lot harder to master. Lives factory library is probably higher quality but more experimental while Reasons is more bread and butter and practical.