Computer is great. I have last years one with a heart rate monitor and it is accurate to +/- 5 BPM so it will do the job.
Also, their riding glasses are the only ones I use. £3 a pair. I have 3 all with different colour lenses in.
Snapped a pair a few weeks back so bought another set. Saves spending £100 on specialized ones everytime you fall off the bike and land on your face!