Eclipse seem to have improved but we haven't seen a lot of feedback for them lately, not sure why that is, although they do have fewer customers having lost many to the bigger and cheaper solutions and a rough patch of bad performance.
Xilo are the more credible option, although as you point out their allowance is significantly lower but then you do pay a few pounds less. You could of course pay for the connection fee and get a 1 month contract, which costs a fair bit more but then at least you can move if Eclipse doesn't work out.
Mark 'Winter' Jackson
Editor-in-Chief - ISPreview.co.uk