Hiya sorelip, good to see you!
mopsy, I owned a Maclaren Techno XT with DD1, bought a phil n teds for DD2 (23 month age gap) and am now back to a Maclaren Techno XT for DS (as I was so impressed with my first one). Comments:
The maclaren Techno XT is suitable from birth, it has height adjusting handles, I'm five foot 8 but like the "high" setting, my friend is 6 foot and says that it's confortable to push. The cheaper Maclarens (Volo, quest) do NOT have height adjustable handles.
It goes well on pavement woods paths, light mud, shingle, towpaths, less well on soft sand/heavy squelchy mud/deep snow.
The under-buggy storage is the only downer: it's pants. However the maneuverability and life of the buggy are hard to beat. It has a
decent raincover, and a pocket for this (no sunshade but a universal factor 50+ "Snoozeshade" cover is less than £20 and fits it well).
When we bought the P&T i kept the maclaren in the car for when we wanted a single buggy just for DD2 (or took DD2 in the baby sling and DD1 in the buggy). So a single is still useful after you've had DC2.
The phil and ted was great for the two of them, but as DD1 got older she didn't need it, it's IMHO too bulky to be worth it for a single baby. Totally up to you, but is it worth two years of carting around a larger, heavier buggy than you need, that won't store well in your house, when you could have a single light smallish stroller that umbrella folds and tucks into your car boot/stairs cupboard, and then upgrade?
And this last thingy is a low blow but worth a consider: if you got a P&T specifically for that second baby and then (God forbid) there was a problem conceiving/carrying the beeb,, would it affect how you felt about having that buggy? Probably not but there are some people to whom that sort of thing makes a difference...If you feel it's the right buggy for you then go for it, I was v happy with our P&T, but flogged it and went back to Maclaren for DS because I felt it works better for a single child.