I had my baby 2 years ago. It was a homebirth but they were Homerton midwives and I had all my antenatal care there. No problems at all - they were great.
I'm now a doula so have had a chance to experience births on the birth centre and labour ward as well as other homebirths via Homerton. While it isn't perfect (but where is) I'm a big fan of Homerton and always secretly prefer it to UCLH. I've found them to be responsive, interested, keen to improve if a fault is pointed out.
The facilities are new and shiny and the new birth centre is lovely. They also, unlike UCH, have a real commitment to water birth. If you can't get in one of the pool rooms because they are too busy, or you end up on the labour ward they have mobile pools that can be brought in. At UCH they won't do this in case of flooding so your chances of water birth (if that's what you plan) are lower.
The postnatal wards are a bit grim, but again they are in most places. You can pay for a side room at Homerton if they have one available. It's currently £70 unlike UCLH which charges £250 for a side room.
I've got 2 homebirths with Homerton midwives and a birth centre story on my website here if you want to take a look: hackneydoula.co.uk/?page_id=26
Whipps has quite a few problems at the moment and the facilities, staffing and attitudes are IMO lagging well behind UCLH and Homerton.
I think in terms of travel-time it can sometimes be useful to think about whether you might find yourself wanting to go in earlier than necessary if you have a longer journey (i.e. to UCLH). Most people, once they've learned a bit about the physiology of birth, want to do a big chunk of their labour at home where they are nice and relaxed and not feel any pressure on themselves to leave earlier than necessary in case their labour is still in an early, disturb-able stage.
All that aside, only you know what's going to make you feel comfortable and relaxed on the day!