Hi hogshead,
Not quite the same position as you, but i have experience with a different Anti TNF drug; Humira (Adalimumab) if that helps at all?
I've been on it twice for inflammatory arthritis (with suspected crohn's). The first time was a disaster; developed Iritis (inflammed irises!) really severe fatigue and saw no improvement in my symptoms. At the time I was on high dose methotrexate as well (by tablet). I gave up after about 4 months as I just couldn't take it any longer.
The second time I was on methotrexate by injection (as we realised I wasn't digesting the methotrexate tablets properly) and it couldn't have been more different; I saw a huge improvement within about a week of starting the humira!
I'm now on daily Azathioprine tablets (they work better for me than the methotrexate injections) and fortnightly Humira injections and have achieved a complete clinical remission; perfect blood test results and no symptoms at all, for the first time since I was diagnosed nearly a decade ago.
I've gone from living on the sofa, tired and in constant pain, to playing squash twice a week!! The fatigue I used to suffer terribly from has almost completely gone as well!
The other thing i've found better about the humira is that this winter I've caught fewer colds than I used to on methorexate - my ability to fight off infection seems stronger with the anti-TNF than it was with other immunosuppressants, although from reading arthritis forums I gather that not everyone finds that to be the case. Obvs it's worse than not being on anything, but it's been a lot more bearable this year!
The long term side effects are a bit scary, but since I first considered (and at the time rejected) anti-tnf treatment (about 7 years ago) they have learnt a lot more about them and have tracked the outcomes of lots of people who have used them and have scaled back the warnings significantly.
For me Humira has been a complete wonder drug; it's no exaggeration to say that it's given me my life back. My partner and I are even hoping to start a family soon (after 6 years of trying and failing to get off the methotrexate and get healthy so we could try and start a family)
I really hope the etanercept works for you! Would be interested to know how you get on / side effects etc as if the humira ever stops working for me etanercept would be the next thing on the list for me to try!