My recommendation is just to look for some for a good price (i.e. cheap !). I suspect they're likely all to be pretty similar in quality. Not sure if members here have really had them long enough to have a good idea of reliability over time, but failure doesn't seem to be a common issue (touch wood !).
If you can find some with slim ballasts then they will take up even less room under the engine bay (an advantage on the passenger side where it's much tighter for space), but they could be harder to find and more expensive. Aztecbandit1 did find some Phillips slim ones on eBay for a good price.