There is another reason to be wary... Electronic ballast manufacturers sell them in all shades. I recently bought a batch of them, one of which broke down quite quickly. Being the electronics engineer, I dismantled the ballast and checked. And noticed that several components where missing.
I considered this enough motive to draw the circuit and noticed that the missing parts were:
about filtering RF interference
and protective circuitry (in fact, only a $0.02 diode) which switches off the oscillator if one of the filaments of the tube was bad, thus avoiding potential electronic component breakdown.
So I took all the ballasts back to the seller and selected one, only slightly more costly, and never looked back. They've been doing their job for over 6 years now.
Conclusion, buy a reputable brand... even if it's slightly more costly.
A note about the RFI itself: It will probably not be the electronics themselves that cause the RFI. The oscillator and choke use ferrite cores which are quite autoshielding. The real culprit for the RFI is the cabling in the tube mounting apparatus (and not to forger the tube itself).