Seed starting: Greenhouse versus my house

For the past 10 years I have become proficient in growing my garden veggies and annuals in my basement with six florescent lights above wire shelves. Its works well but things get crowded when I pot up and begin to move trays of six inch plants inside and out as part of hardening off.

A greenhouse appeals to me and I have the opportunity to use salvaged double pane windows to build an 8x10 foot greenhouse in an optimum southern exposure. I am quite handy and with guidance from the Greenhouse Forum folks, confident I can build a suitable structure. It would be used primarily in late winter/early spring for starting veggie/annual plants and as a seson extender for hardier veggies. probably will not have auxillary heat but it could be so equipped in a smaller area for tender starts like tomatoes etc.

If I do go with a greenhouse, how will my seed starting process change in terms of things like timing of seeding, need for heat, other cultural practices in general that I may not be aware of? Will it get me starts any sooner or at about the same time with less crowding or tray moving that I do now? Will they be hardier and need less work to preevnt them from gettiing leggy that can happen under the lights? Is there any advantage to one method over the other?

Thanks for any input you all may have.