I have also since read a few reviews on how difficult it is to get to silver and also how difficult it is to actually book flights with your accumulated miles
I've been in the BA Executive club since I had to go on a trip from work some years ago. I no longer travel with work but collect via Tesco - I also have a Tesco credit card, so they build up quite nicely. I have never found it too difficult to book flights with my miles, as long as I book well in advance and have had quite a few flights paying taxes and charges only. I've never worried about the "tier points", I've only ever been blue and I'm not sure of the advantage, other than special lounges, etc.
I have however noticed that the "taxes and charges" have crept up and now there are fewer direct flights from Manchester, it is becoming less useful to me. I have noticed that Airmiles have re-introduced fixed miles for routes,
inclusive of taxes and charges and using various different airlines. I may switch Tesco points back to Airmiles in future, as I have both accounts.