15 openings with sometimes 3 windows in one opening is a lot of windows. You would have to count the actual windows. Multiple casements are individual windows, whereas 3 lite sliding windows is 1 big window, not 3. Casements are a little more expensive. I can't say if the price is right or not, because I don't know the amount and size of the windows. It "sounds" like it's in the ball park, depending on installation methods, etc. However I can say if it were me I wouldn't do Pella as their reputation is not stellar. I would recommend you get the Marvins priced as well, and hopefully you will find that the price isn't out of the ball park. Not knowing all the details of your job, it's hard to recommend something for you with certainty.

+1 on WindowDog, is a aluminum clad window the quality of the cladding is far superior in the Marvin to the Pella. and in actuality the entire Marvin unit is higher quality than a Pella unit. Pricing I cannot be certain but a reputable local dealer should be a good guide for you.

+1 to the above comments. Not only is Marvin a better functioning window but you mentioned dark colors and that is also a major difference between the two manufacturers. Pella uses roll formed (thin) aluminum on the sash or operating parts of the windows and extruded (heavier) aluminum on the frames. You get a different fade rate between the two because you cannot coat the thinner aluminum as well. After as short a time as two years on the sunny side of your house, you will see a difference with Pella. The sash will be lighter than the frames.
Marvin uses extruded on both sash and frames as well as a the highest rated finish backed by AAMA. As for pricing, there should be a very small difference between Marvin and Pella Architectural.

+1

Not at all out of the range of normal pricing and if you get a premium wood (i.e. Marvin or Kolbe & Kolbe) it might be considered cheap.

Have you considered fiberglass instead of wood?

Which Marvin windows can I expect to be around the same price and quality as the Pella Architect, Marvin Ultimate? How much of a +/- should I expect on the price?

My understanding is fiberglass (suggestion from previous poster) is available only on the Marvin Integrity line. Correct? Is this a lower end product than Marvin Ultimate/Pella Architect?

No comparison between the Ultimate and the Architect. The Marvin is miles ahead in materials, looks, and quality.

Marvin is also available in the Ultrex (Fiberglass) Infinity series too.

Yes the Marvin Integrity is a lower end window (not quality wise) compared to the Ultimate. Integrity was introduced to get Marvin a bit of a lower price point window for the semi custom market to compete price wise with Andersen, etc. The product is still far superior to anything even close in its price range. They attempt to keep the price point down by somewhat limiting the custom options and keeping to mostly standard sizing. Where the Infinity is made using basically the same technology but all Ultrex and was originally introduced as a "replacement" or insert type of window.

My only issue with the Integrity after looking into it extensively is the options for outer color are limited. The best we could do was bronze but it is pretty dark/grayish for my liking.

The Marvin Ultimate offers a 'Bahama Brown' color which is pretty close to what we have now. We like this color.

I appreciate all the advice and feel like I am making a more informed choice. I have to price out the Ultimates and see if it is worth the cost over the Pella Architect.

I think the Marvin Ultimate is the better window but if it is much more expensive I'm OK with Pella Architect even though I know Pella gets mixed/negative reviews. I will most likely end up with one of those windows. I will post the price point on the Marvin Ultimate (from the same place that gave us the Pella price quote) and hopefully let me know how good/bad it is.

Bahama Brown is available in the Infinity as well.

You would be better suited getting the Infinity if you want the Bahama Brown rather than the Pella Architect.

I'd definitely get it quoted. Just because Marvin is typically more costly, that does not mean that your quote for it will be more. Pricing varies greatly from dealer to dealer, so it is very possible that your Marvin quote could come in lower. Personally, I pay less for Marvin than I do for Pella.
The Architect series is not a bad window, IMO, but I'd choose the Marvin for my money. As mentioned, any of Marvin's lines would be a better choice.

Eagle has a myriad of exterior colors and has an extruded aluminum exterior as well. They are typically cheaper than Marvin's Ultima and more than Pella with same options. They also have very nice exterior casing options like Marvin and Pella

From my perspective you may also wish to look at Kolbe as well, in my opinion a better option than either Pella or Eagle and a very small step below Marvin Ultimate in terms of quality (in fact there are some things they do that I prefer over Marvin)

+1

I would not put Pella or Eagle in the conversation with Kolbe or Marvin.