If you are only planning on going no more then stage 2, then in my opinion Bluefin will best suit.
Only if want to go stage 2+ will revo give better dividend.
You dont need a select switch for a stage 1 map. Total waste of money.
At least with bluefin you keep your VW stock map on its handset which takes 5-6 minutes to re-install for a dealer Visit.
Revo give you a Mock version of your origonal map.It will also add to the cars flash counter, whereas bluefin doesnt.
Standard GTi stage 1 will get you between 230-235bhp.
If you have an Edition30/pirelli, expect towards 280bhp.
For nearly a £300 mark up for revo with sps switch to Bluefin with handset, map, and your origonal map as a 2nd choice. I know which id plump for.
Tis up to you of course fella.