I own both of these markers.
personally i would deffinately go for the ION . Its lighter, quieter and would do ok whether your just Rec-Ballin or just starting out to get into tourneys.
The stock Electra just Sucks...i have mine upped to the max ,with lighter internals(cycles faster) , higher flowing , low pressure, and is a lot quieter now, but is very costly and time comsuming to get it to that. But has been fun...
You will also find it hard to get parts for spyders in the UK. With all that effort i i put into it, i still love it, and use it for rec-ball.
Ask "COV BOY", i gave him the same advise on the kingsman forums about a month ago when he just started out. I believe his sold his Electra now..
ION's have a better resale value, try to save more cash for a better high end marker ,rather putting that spare cash towards up's.
im now rocking the Arsenal G7 Fly, but still have love to play with my other 2 markers.