I agree with Bradford. A SP 450 is just too small to practically cook with. For solo use, I prefer an SP 600. It gives just the right amount for a solo freezer bag meal and a hot drink, or if cooking for 2, it boils the perfect amt of water for a 2 person meal. Also, Jason Klass and Minibulldesign make aluminum lids for SP 600 and higher.
I've handled the REI ti Kettle in person, and feel that there are better alternative for the money. Specifically, the kettle is too tall to serve as a proper kettle. Also, the weird bulge makes cleaning, eating awkward if you cook in the pot
You can either get this instead
http://www.rei.com/product/649902
Which is great for 2 people cooking, or pasta making. It has the tightest fitting lid out of all the pots on the market right now.
If you like the idea of a teapot, I think youll be better off with this
http://www.rei.com/product/768513
Cheaper, large capacity, conducts heat better. Strong, as its anodized aluminum. And its wide! conducts heat over a greater surface area….making it pair up with a pepsi can perfectly.
If you think youre gonna be using both a pocket rocket (very narrow focused flame) and a pepsi can stove (wider flame)..i think you best bet is to get a pot that can use both types of flames. I think a MSR titan kettle is more suitable. A wide pot like a kettle, wont be the best match for a pocket rocket, while SP 600 doesnt work that well with wide base flame stoves like pepsi can stoves. As reference, I currently own a pocket rocket, numerous pop-can stoves, and all the pots (except for the rei kettle which ive only handled) that ive mentioned. Hope this helps!