The Philips Agrolite XT was designed for magnetic ballasts, not sure if it will run on all electronic ballasts. Other than that, Philips is a rock solid brand.
I am currently using the Hortilux HPS on an Xtrasun Dial-a Watt, no complaints. After a year of use, it does not appear to have deteriorated much, I see no need to replace it yet.
Funny thing about Gavita: their Digistar ballast is recommended to be used with a Gavita bulb. Somebody find me a 1000w Gavita SE bulb in the USA; I can't find one for sale anywhere. I don't buy from companies that have distribution problems if I can at all avoid it.
The DE bulbs have some advantages but the reflectors are limited selection and usually expensive. Far as I can tell, they come in one size: 1000 watt. I like to be able to swap ballasts and bulbs around depending on conditions. Furthermore, the lumen maintenance of SE bulbs is perhaps a lot better than it used to be due to electronic ballasts of increasingly high frequencies.
The growerhouse site has a test that purportedly tests SE vs. DE. But if you look at the numbers and then look at the reflector designs, what they are really testing is reflectors. A reflector designed to concentrate light in a small area is going to produce higher numbers. Reflector choice is at least as important as choice of bulb.