Is this Wildwoodz famous Gambo?
Id go for:
Ego6
E-tek
Ego5
All are great guns but the 06 ego is slightly newer so is likly to have less wear and tear, with the advent of the 08 prices are +/- 300 mark & they use the same detents as the 07/8 so there will be plenty around.
I love the LCD screen and although the e-tek is pretty easy to change the settings the LCD is brilliant.
The E-tek does have certain pluses over the 06 such as the microswitch rather than opto board so the trigger pull is slightly nicer and it is the lightest out of the three markers. and you can get some great examples of them for £210 - "Jacko" has a very nice one for sale at the moment.
In short, if you have the ££ i'd go for the 06 but for the saving the E-tek is still a fantastic marker
I've owned all 3 (currently got an 06) so if you have any questions i'll do my best to help.