Have the UltraLite and the SV Revo/DART. Two very different animals.
The SV Revo/DART on my T1 base heats and starts producting vapor in under 10 seconds. The batteries last for dozens and dozens of hits before needing to be recharged (maybe a hundred hits). So many that I never counted, and I can't remember ever having to change batteries due to running out of juice, except when I deliberately ran a pair down to see how long they would last (more than one day of heavy vaping). Consequently, I never have to worry about the battery state, and if I'm going to be away from a charger for days, I really only have to bring a single spare set of batteries with me.
The UltraLite is tiny, goes through the TSA (airline security) with no problems, and is really really stealthy. The battery doesn't last very long, and you have to always pay attention to its charge state as you only get about a dozen hits out of one battery. Warmup time is about 20 seconds. Carrying a few 10440 batteries is trivial, as they take up next to no space, but again you wind up having to pay attention to your battery state. "Is my hit barely producting vapor because I have to reload my oil, or because my battery is going dead?" And because the UltraLite battery only gives you maybe a dozen good hits, it "hurts" when you have to waste one hit worth of battery to see that the core is glowing, and that you needed more oil, not a fresh battery.
The Ultra (as opposed to the UltraLite) mostly ameliorates this. The Ultra battery provides two or three times as many hits as the UltraLite battery. Good, strong hits. So if you do decide you want to go the Ultra/UltraLite route, I would seriously consider the Ultra the way to go. If you decide you want to use a T1 size battery holder, I would go with OF's advice and get the LV version unless you already have some SV stuff.